Chapter IV: Part 4

I am called upon either to establish this new genus among the _Sciænidæ_, or to break down one of the essential distinctions set by Cuvier between this family and the _Percidæ_. The form is so completely that of a _Serranus_,—which it resembles especially in its dorsal fin, head, maxillary teeth, form and armature of the pieces of the gill-cover, and in the arrangement of the scales on the body,—that at first sight no one would hesitate to refer it to that group; but _the vomer and palatines are without teeth_.[21] In this respect, indeed, I consider it an important discovery; as it affords another striking instance of the uncertainty of this character, in cases in which others, which have been generally made subordinate to it, remain constant. It is probable that the time will come, when it will be found necessary to revise some portion of the _Percidæ_ and _Sciænidæ_ with reference to a more correct valuation of this character. For the present, however, I refrain from interfering with the Cuvierian arrangement; and the only alternative is to consider this as a new form among the _Sciænidæ_, where it must be placed along with those genera possessing one dorsal fin, and having seven rays in the branchiostegous membrane. Such are _Hæmulon_, _Pristipoma_, and _Diagramma_; from all which, however, it is at once distinguished by the absence of pores at the symphysis and on the lower jaw, and by the much more developed spines on the opercle, and from _Pristipoma_ by its having, further, scales on the vertical fins. On the whole, it seems to approach nearest to _Hæmulon_; but the crown and snout are more free from scales than in that genus, and the scales on the body are not set in oblique rows, as is the case in so many of the true _Sciænidæ_. The head also has no cavernous appearance about it. This new form is from the Galapagos Archipelago.

PRIONODES FASCIATUS. _Jen._

PLATE IX. Fig. 1.

_P. pallidè flavescenti-fuscus, fasciis transversis plurimis suprà
rubescenti-nigris infrà miniatis; pinnis verticalibus maculis parvis
ocellatis: vertice, rostro, et maxillis, nudis; preoperculo margine
adscendenti denticulato, basali lævi; operculo mucrone intermedio
forti; spinis dorsalibus ad apices laciniis investitis; pinná
caudali subæquali._

B. 7; D. 10/12; A. 3/7; C. 17; P. 18; V. 1/5.
LONG. unc. 7. lin. 3.

FORM.—Oval, compressed; the back not much arched, forming one
continuous curve with the profile, which falls gently from the nape;
ventral line less convex than the dorsal. Greatest depth equalling
one-fourth of the entire length; head about one-third; thickness
rather less than two-thirds of the depth. Mouth rather wide, with
the lower jaw longest. The maxillary dilates at its posterior
extremity; it reaches to nearly beneath the middle of the orbit, and
does not retire beneath the suborbital. In each jaw a band of
velutine teeth; above there is an outer row of longer ones in card,
and one or two in front on each side still longer resembling small
canines; in the lower jaw there are also a few longer ones, of the
same character as these last, interspersed at intervals. Tongue free
at its extremity, and, as well as the vomer and palatines, without
teeth. Eyes rather high in the cheek; their diameter about one-sixth
that of the head. The nostrils consist of two small round orifices a
little in advance of the eyes, the anterior one covered by a
membranous flap. Margin of the suborbital entire. Preopercle finely
denticulated on its ascending margin, which is vertical and slightly
convex; but the denticulations almost disappear at the angle, and
are not visible at all on the basal margin. Opercle triangular, with
three flat spines, the middle one longest, beyond which the membrane
projects in the form of an angular process to the distance of three
lines. Small scales on the cheeks and preopercle; but none on the
crown, snout, first suborbital, maxillary, or lower jaw; scales on
the opercle larger, equalling those of the body in size.
Gill-opening large, with the branchial membrane deeply notched in
the middle.

Lateral line following the curvature of the back at one-fourth of the
depth. Scales on the body moderately large: one taken from the
middle of the side above the lateral line is of a somewhat oblong
form, with the free edge rounded and finely ciliated; the basal
portion with fourteen slightly converging striæ, which form at the
hinder margin as many, but not very distinct, crenations.

The dorsal commences above the terminating lobe of the opercle, and
reaches to within a short space of the caudal: height of the spinous
portion, which, with the exception of the first two spines, is
nearly even throughout, about one-third of the depth; soft portion
rather higher, with the last two rays but one longest, and forming a
point backwards; all the soft rays branched. Anal commencing in a
line with the soft portion of the dorsal, and terminating a little
before that fin; three spines, the second one-third longer than the
first, and a little longer than the third, and much the strongest of
all; the soft portion of the anal is similar to that of the dorsal,
and terminates in like manner in a point behind. Space between the
anal and caudal a little less than one-sixth of the entire length.
The caudal appears to have been nearly even, or perhaps slightly
rounded, but the rays are worn. Rows of very minute scales, not very
obvious, between the rays of all the vertical fins. Pectorals
slightly rounded; more than half the length of the head; all the
rays with the exception of the first two and the last, branched.
Ventrals attached beneath, or perhaps a very little in advance of
the pectorals; pointed, with the second soft ray longest. No
lengthened scale or process of any kind in the axilla of either
ventrals or pectorals; neither are the former fastened to the
abdomen by a membrane half their own length, as is the case in many
of the _Serrani_.

COLOUR.—“Pale yellowish brown, with numerous transverse bars, of which
the upper part is reddish black, the lower vermilion red;
gill-covers, head, and fins, tinted with the same.”—D. Mr. Darwin
has not noticed some small round black spots surrounded by a white
border, and having an ocellated appearance, which are very evident
on the upper half of the soft portion of the dorsal: there is a
faint indication of similar spots on the anal and caudal.

Habitat, Chatham Island, Galapagos Archipelago.

_Fish. Pl. 10._

_W. Hawkins del^t._

_Pristipoma cantharinum. Nat. Size._
]

Mr. Darwin obtained one specimen only of this new genus at Chatham Island in the Galapagos Archipelago. It is probably not full-sized.

PRISTIPOMA CANTHARINUM. _Jen._

PLATE X.

_P. cæruleo-argenteum, operculo nigro-marginato: pinnâ, dorsali
subæquali, spinis ultimis radiis articulatis paulo brevioribus;
anali spinâ, secundâ forti, longitudinaliter striatâ, radiis
articulatis duodecim: preoperculo rectangulato, margine adscendenti,
leviter denticulato, basali integro: vertice, buccis, et ossibus
opercularibus, squamatis; rostro ultrà nares, suborbitalibus, et
maxillis, nudis; squamis corporis ciliatis: pinna caudali furcatâ._

B. 7; D. 12/15; A. 3/12; C. 17, et 4 breviores; P. 20; V. 1/5.
LONG. unc. 10. lin. 11.

FORM.—Form oblong-oval, much resembling that of the _Cantharus
griseus_. Body compressed, with the dorsal line slightly curved; the
profile descending from the nape more obliquely, and in a very
regular manner. Greatest depth beneath the commencement of the first
dorsal, contained not quite three times and three quarters in the
entire length: head rather less than one-fourth of the length. Mouth
protractile, but not wide, the commissure not extending to a
vertical from the anterior angle of the eye; when closed, the
maxillary retires beneath the suborbital, and only just the
extremity remains visible. Jaws equal; in each a narrow band of
velutine teeth, the outer row somewhat longer than the others,
particularly above, where they approach to card. Tongue, palatines,
and vomer smooth. Eyes moderate; their diameter rather less than
one-fifth of the length of the head; rather nearer the extremity of
the snout than the posterior margin of the opercle; the distance
between them equalling twice their diameter. Two small pores and a
fossule beneath the symphysis of the lower jaw, the latter very
distinct. Preopercle rectangular, the angle somewhat rounded; the
ascending margin nearly straight and finely denticulated, but the
denticulations hardly continued to the angle, and not appearing at
all on the basal margin. Opercle with two small flat points, but
very indistinct and almost lost in the membrane. Suborbitals large,
with their lower margins entire. Crown, cheeks, and pieces of the
gill-cover, covered with small scales; but not the snout in advance
of the nostrils and eyes, nor suborbitals, nor lower jaw.
Suprascapulars marked by a large scale, the margin of which is
nearly entire.

Lateral line following the curvature of the back at one-third of the
depth; each scale marked with an elevated line without
ramifications. A scale taken from above the lateral line is of a
somewhat rhomboidal form; the free portion very finely striated,
with the margin finely ciliated; the concealed portion with eight or
nine deeper and more distinct striæ, not meeting in the centre to
form a fan, and with the basal margin crenated. The scales on the
cheeks and opercle are smaller than those on the body, and almost
smooth.

The dorsal fin commences in a line with the posterior margin of the
opercle, and extends nearly the whole length of the back, rising
from a groove as in the _Sparidæ_: its height on the whole tolerably
uniform throughout: spinous portion occupying more than half the
fin; the anterior spines gradually increasing in length to the
fourth,[22] which equals rather more than one-third of the depth;
the succeeding ones nearly even, very gradually decreasing to the
last, which is about two-thirds the length of the fourth; all the
spines moderately stout: soft portion of the fin even, and rather
higher than the last spine. Anal commencing in a line with the third
soft ray of the dorsal, and terminating opposite to that fin: the
first spine short, but strong; second and third spines equal in
length, being about two-thirds the length of the soft rays, but the
second much stouter than the third; the second spine is also
distinguished from the others by having its surface longitudinally
striated: soft rays nearly even, and resembling those of the dorsal.
Caudal forked, with the upper lobe a trifle longer than the lower;
the basal half covered with minute scales. Pectorals narrow and
pointed, about two-thirds the length of the head, with a small fold
of loose skin in their axillæ. Ventrals placed a little further back
than the pectorals, and somewhat shorter; a long pointed scale in
their axillæ, nearly one-third their length.

COLOUR.—“Bluish silvery.”—D.—The colour, as it appears in spirit, is
nearly uniform bluish gray, and very similar to that of the
_Cantharus griseus_. The gill-cover has a dusky edging posteriorly.

_Second specimen._—Smaller than the above, and not quite so deep in
the body; the greatest depth contained a trifle more than four times
in the entire length; the nape in consequence less elevated, and the
profile less oblique. Eyes relatively a little larger, their
diameter rather more than one-fifth the length of the head.
Preopercle with the posterior margin not so rectilineal, approaching
to concave; the angle at bottom projecting in consequence a little
backwards; the denticulations not quite so distinct and regular. One
ray more in the soft dorsal.

D. 12/16; A. 3/12; C. 17, &c.; P. 19; V. 1/5.=
LONG. unc. 9. lin. 2.

COLOUR.—“Silvery; above, shaded with brown and iridescent with blue;
fins and iris sometimes edged with blackish brown. Flap of the
gill-cover edged with black.”—D.

Habitat, Galapagos Archipelago.

This species, which is undoubtedly new, may be known from most of those described by Cuvier and Valenciennes by its greater number of soft rays in the anal fin. The only ones which equal it in this respect are the _P. Conceptionis_ and the _P. fasciatum_; from the former of which it may be distinguished by its greater depth and nearly even dorsal, from the latter by its plain colour free from all conspicuous bands and markings. The dorsal notch is scarcely observable, the eleventh and twelfth spines being nearly equal, and but little shorter than the first soft ray. Its analogy to the genus _Cantharus_ among the _Sparidæ_, which it resembles as well in colour as in general form, is very striking. There are two specimens in the collection; the one described first above having been taken at Chatham Island, the other at Charles Island, in the Galapagos Archipelago.

1. LATILUS JUGULARIS. _Val._

Latilus jugularis, _Cuv. et Val._ Hist. des Poiss. tom. ix. p. 369. pl. 279.

FORM.—Elongated, with the dorsal line slightly curved, the ventral
nearly straight. Greatest depth contained five times and one-third
in the entire length. Head, which much exceeds the depth, four times
in the same. Profile very convex above the eyes, whence it falls
obliquely to the lips. Snout thick and rounded, resembling that of
the _Red Mullet_: mouth protractile, horizontal, placed at the
bottom of the snout, the commissure just reaching to a vertical from
the anterior part of the orbit. Jaws equal or very nearly so; the
lower one perhaps a very little the longest. Maxillary not widening
at its posterior extremity. A band of velutine teeth in each jaw,
narrowing at the sides as it extends backwards; with an outer row of
longer and stronger ones: in the lower jaw, the velutine band does
not extend beyond the middle of the sides, the carding teeth being
all that are visible. Tongue and palate smooth. Eyes high in the
cheeks; large, and of an oval form; their vertical diameter
three-fourths of their longitudinal; this last equalling one-fourth
the length of the head. Nostrils consisting of two round apertures,
the posterior one largest, the anterior covered by a membranous
flap. Preopercle with the denticles far apart, and not very obvious,
unless the skin be dissected off; the ascending margin rectilineal
and vertical; the angle rounded. Bony part of the opercle
terminating in a flat point, above which are two other smaller
points not so well developed; all the points concealed in the
membrane, and scarcely visible from without: beneath the principal
point, the membrane is prolonged backwards in the form of a broad
flattened bristly point three lines in length. Crown, gill-covers
and cheeks, scaly, but not the jaws; snout scaly, except very near
the lips. Gill-opening large.

Lateral line at first at one-third of the depth, but falling gradually
to one-half. Scales rather small; one taken from immediately above
the lateral line of an oblong form, the length being twice the
breadth, with its free margin finely ciliated, crenated behind with
a fan of nine striæ; on scales taken from other parts the number of
striæ in the fan are more numerous.

One long dorsal fin of nearly uniform height throughout, equalling
about half the depth; only four slender spines, gradually increasing
in length from the first which is very short; the fourth about
three-fourths the length of the first soft ray; soft rays increasing
likewise very gradually to the fourth, which with the next five or
six are highest; the membrane of the fin very delicate; all the soft
rays branched. Vent in a vertical line with the ninth soft ray of
the dorsal. Anal commencing immediately behind it, and answering to
that portion of the dorsal to which it is opposite, terminating at
the same distance from the caudal; only two slender spines, the
first very short; the first soft ray simple, the rest branched.
Space between these two fins and the caudal barely one-eighth of the
entire length. Caudal nearly even. Pectorals moderately long and
narrow, equalling nearly the length of the head; rays branched;
fourth, fifth, and sixth longest. Ventrals a little in advance of
the pectorals, nearly equalling them in length; of a pointed form,
with the third and fourth soft rays longest. In the axilla of the
pectorals a vertical scaly membranaceous lamina.

B. 6; D. 4/28; A. 2/22; C. 17; P. 20; V. 1/5.
Length 11 inc. 5 lines.

COLOUR.—(_In spirits._) Dusky olive on the back and upper part of the
sides, yellowish (probably silvery in the recent state) beneath,
with faint indications of five or six dark transverse bands, similar
to those in the _common perch_. Inside of the ventrals blue.

_Second specimen._—Smaller than the above, measuring six inches and a
half in length, but differing from it in no respect, as regards
form, excepting in having the profile not so oblique, and the snout
in consequence not so obtuse; the jaws also are exactly equal.
Fin-ray formula the same.

COLOUR.—“Beneath brilliant white; head and back clouded with purplish
and carmine red; longitudinal and transverse irregular bands of the
same.”—D. The bands in this specimen amount to eight in number, and
are much more conspicuous than in the larger one above described.

Habitat, Valparaiso, Chile.

The smaller of the two specimens above described was taken by Mr. Darwin at Valparaiso. The number attached to the larger one has been lost, but it was probably taken at the same place, where it had been previously discovered both by M. D’Orbigny and M. Gay. The specimen described by Valenciennes has one soft ray more in the dorsal, and one less in the anal, than either of the above; but in all other respects they tally exactly. As observed in the “Histoire des Poissons,” this species has many points of resemblance to _Percis_ and _Pinguipes_.

2. LATILUS PRINCEPS. _Jen._
PLATE XI.

_Fish. Pl. 11._

_W. Hawkins del^t._

_Latilus princeps. ½ Nat. Size._
]

_L. elongatus; corporis altitudine capitis longitudinem æquanti;
dentibus velutinis, serie externâ fortiori, aculeiformi; preoperculo
margine adscendenti recto, leviter denticulato, basali lævi;
operculo mucrone unico; rostro, ossibus suborbitalibus, maxillis,
limbo preoperculi, et interoperculo, nudis; buccis et cranio
squamatis, squamis in vertice spatium angulatum inter oculos
occupantibus; pinnis dorsali analique prælongis; spinis analibus
parvis, gracilibus, primâ minutissimâ; ventralibus accuratè
thoracicis; caudali emarginatâ._

B. 5?; D. 8/26; A. 2/26; C. 15, &c.; P. 18 vel 19; V. 1/5.
LONG. unc. 20. lin. 6.

FORM.—Elongated; the greatest depth equalling the length of the head,
and each contained rather more than four times and a half in the
entire length. Snout short and rather obtuse, the profile bending
downwards in a curve before the eyes. Mouth nearly horizontal, at
the bottom of the snout; when closed, the maxillary, which is not
widened at its posterior extremity, and which is very similar in
form to that of the last species, reaches nearly, but not quite, to
a vertical from the anterior part of the orbit. Lower margin of the
suborbital entire. Teeth forming a velutine band in each jaw, widest
in front, with a row of stronger ones externally: none on the
tongue, vomer, or palatines. Eyes large, and high in the cheeks;
their diameter one-fifth the length of the head. Preopercle with the
angle at bottom rounded; the ascending margin straight, and nearly
but not quite vertical, forming with the basal rather more than a
right angle; the former finely denticulated, but not the latter.
Opercle terminating in one flat point, not projecting beyond the
membrane. The branchiostegous rays appear to be but five in number,
but, the skin being dry, there may possibly be a sixth overlooked.
Cranium, cheeks, and opercle scaly; but not the snout or jaws, or
limb of the preopercle, or interopercle: the scales on the crown are
separated from the naked skin of the snout by a well-defined line,
which forms an advancing angle between the eyes.

Lateral line straight, and continued to the base of the caudal; its
course parallel to the back at between one-fourth and one-third of
the depth. Scales on the body rather small, oblong, longer than
broad, with their free extremities dotted and finely ciliated; the
concealed portion striated finely at the sides, and more deeply at
the base; but all the central portion, including an oblong area of
the same form as the entire scale, without striæ, being only very
minutely roughened or punctured.

One long dorsal, low, and of nearly uniform height throughout,
commencing about in a line with the insertion of the pectorals, and
reaching very nearly to the caudal: eight spines, rather slender,
and very gradually increasing in length, the last being just twice
the length of the first and equalling the distance from the base of
the fin to the lateral line: the soft rays which follow are nearly
even with the last of the spinous till the twenty-fourth, which is
slightly prolonged in a point, and which is followed by two others
shorter than the rest; the ends of the rays are rather worn, but
they appear to have been all branched. Anal also long, commencing at
about the middle of the entire length, or in a line with the sixth
soft ray of the dorsal, and terminating opposite to that fin, to the
last half of which, or rather more than half, it exactly answers;
only two spines, which are so slender and minute, especially the
first, and so closely united to each other as well as to the first
soft ray, as to be scarcely obvious except upon dissection; all the
soft rays, except the first, branched. Space between the anal and
caudal not a tenth part of the whole length. Caudal slightly
notched, or hollowed out, with rows of scales between the rays.
Pectorals pointed, about three-fourths the length of the head, with
the seventh and eighth rays longest; rows of scales at the base
between the rays: in their axillæ a somewhat projecting vertical
scale or lamina, as in the last species. Ventrals immediately
beneath the pectorals, also pointed, but shorter.

COLOUR.—“Above, and the fins, obscure greenish; sides obscure coppery,
passing on the belly into salmon-colour. Pectorals edged with dull
blue. Iris yellowish brown: pupil black-blue.”—D.—The skin has dried
to a nearly uniform brown.

Habitat, Chatham Island, Galapagos Archipelago.

I feel but little hesitation in referring this species, which is one of the many new ones obtained by Mr. Darwin in the Galapagos Archipelago, to the genus _Latilus_. The absence of vomerine and palatine teeth requires it to be placed, according to Cuvier’s views, among the _Sciænidæ_; in which family, there is no other group besides _Latilus_, to which it makes any approach. It agrees with that genus in its general form, and in many of its particularities; it has the same form of snout, mouth, maxillary, and dentition; the same scaly lamina in the axilla of the pectorals; the same long undivided dorsal and anal fins, with only two very small anal spines, so closely united to the first soft ray as to be easily overlooked. But it may be at once distinguished from the _L. argentatus_ and the _L. doliatus_, the only two species described by Cuvier and Valenciennes in the body of their work, by its much more numerous soft rays in the dorsal and anal fins. From the _L. jugularis_ last described, which resembles it in this respect, it differs in its thoracic ventrals, shorter head, naked snout and suborbital, and notched caudal: the profile also falls less obliquely. There is only one specimen in the collection, a dried skin and rather injured.

HELIASES CRUSMA. _Val._

Heliases Crusma, _Cuv. et Val._ Hist. des Poiss. tom. ix. p. 377.

FORM.—Oval, very much compressed. Back considerably elevated,
particularly at the nape, whence the profile descends very
obliquely, and, with the exception of a slight concavity before the
eyes, in nearly a straight line. Greatest depth at the commencement
of the dorsal, equalling nearly half the entire length, caudal
excluded. Head contained four and a half times in the same. Snout
short: mouth small, a little protractile: lower jaw rather the
longest. A narrow band of velutine teeth in each jaw, with the outer
row in fine card; these last longest and strongest in front. Eyes
large; their diameter nearly one-third the length of the head.
Suborbitals forming a narrow curved band beneath the eyes, and
covered by a row of scales. Nostrils with only a single, small,
round aperture. Preopercle with the ascending margin vertical, not
quite rectilineal, inclining slightly inwards towards the angle,
which is rounded. Opercle, taken together with the subopercle, very
regularly curved, the margin describing nearly a semicircle, with
one flat point to terminate the osseous portion; its height double
its length.

The whole of this fish, including every part of the head, except the
lips and maxillary, is covered with scales, which extend on to the
vertical fins as in _Glyphisodon_: those on the fins and upper part
of the head and snout are very small, but those on the gill-covers
and body very large: about twenty-six or twenty-seven in a
longitudinal line from the gill to the base of the caudal, and
fourteen or fifteen in a vertical line: one taken from about the
middle of the side is oblong, the breadth exceeding the length, with
the anterior margin rounded, and the free portion finely dotted and
very minutely ciliated, the concealed portion cut square, with a fan
of eight or ten striæ not meeting at the centre, and terminating at
the basal margin in as many crenations. The lateral line commences
at one-fourth of the depth, but, from the fall of the dorsal line
posteriorly, the distance between these two lines diminishes as the
former advances: the lateral line terminates beneath the soft
portion of the dorsal fin altogether.

Fins almost exactly similar to those of the _Glyphisodon saxatilis_
and _Heliases insolatus_, as described and figured in the “Histoire
des Poissons.” The fourth and fifth spines in the dorsal longest,
equalling one-fourth of the depth; of the soft rays the third,
fourth, and fifth are longest. First anal spine only one-third the
length of the second, which is itself rather shorter than the soft
rays; and these last appear longer than in the _H. insolatus_.
Caudal more forked than crescent-shaped, the depth of the fork
equalling nearly half the length of the fin, which is itself
one-fourth the entire length of the fish. Axillary scales of the
pectorals and ventrals as in _H. insolatus_.

B. 6; D. 13/12; A. 2/12; C. 15, & 4 short; P. 21; V. 1/5.
Length 8 inches.

COLOUR.—“Above lead-colour, beneath paler.”—D. In spirits, it appears
of a deep brownish olive on the back and upper part of the sides,
passing into dull golden yellow on the lower part of the sides and
abdomen, where, however, the scales are still faintly edged with the
former colour. Fins dark.

Habitat, Valparaiso, Chile.

This species, as M. Valenciennes observes, is so extremely similar to the _H. insolatus_, that at first sight, it would hardly be distinguished from it. The only differences appear to consist in the form of the caudal, which is forked, not crescent-shaped as in the species just mentioned, and in the greater length of the soft rays of the anal. In the figure of _H. insolatus_ in the “Histoire des Poissons,” these rays are represented of the same length as the second spine, whereas in the present species they rather exceed it, giving a greater depth to the entire fin. The teeth also would seem to be more developed in the _H. Crusma_, especially those in front, which are longer than the others. According to Valenciennes, the outer row hardly exceeds the inner ones in the _H. insolatus_. The geographical position of the two species is however widely different. The _H. insolatus_ is a native of the Caribbean Seas; whereas the _H. Crusma_ has only been obtained on the coast of Chile and off the island of Juan Fernandez. M. Gay first obtained it at Valparaiso, where also Mr. Darwin’s specimen was procured; in whose notes it is stated, that it gets to a much larger size than the one here described.

FAMILY—SPARIDÆ.

CHRYSOPHRYS TAURINA. _Jen._

PLATE XII.

_C. albida, quatuor fasciis interruptis nigro-fuscis; pinnis dorsali,
caudali, et ventralibus, clarè cæruleo-marginatis: dentibus anticis
conicis, in maxillâ superiore octo, in inferiore decem minoribus;
molaribus suprà seriebus tribus, intermediâ minori, infrà duâbus
dispositis; preoperculo et operculo, utroque quatuor squamarum
seriebus tecto; limbo preoperculi nudo._

D. 12/12; A. 3/10; C. 17, &c.; P. 15; V. 1/5.
LONG. unc. 14.

_Fish. Pl. 12._

_W. Hawkins del._

_Chrysophrys taurina. ¾ Nat. Size._
]

FORM.—General form not very dissimilar to that of the _C. Aurata_.
Greatest depth contained about three times and a half in the entire
length. Depth and length of the head equal, each about one-fourth of
the entire length. Profile very oblique. Eyes high, and moderately
large, distant two diameters from the end of the snout. Preopercle
with the angle at bottom very much in advance, giving an obliquity
to the ascending margin; the limb not very broad, and naked; in
front of the limb are about four rows of scales smaller than those
on the body: the same number of rows of scales on the opercle. Jaws
equal, with eight conical incisors in front of the upper one, and
ten in front of the lower;[23] those above longer than those below,
and more regularly and closely set: behind the incisors above and
below is a patch of fine card: then follow the molars, which are in
three very regular rows above and two below; of the three rows above
the inner and outer ones are much the strongest, containing each
about eight teeth; those in the outer row are slightly pointed, and
not very unequal in size, but the inner series enlarge very rapidly
as they extend backwards, the last two or three being of
considerable size; all round or nearly so, there being no large oval
one at the back, as in the _C. Aurata_ and some other species; the
middle series above consists of teeth much smaller than the others,
and more numerous: the two rows below are not very dissimilar to the
inner and outer rows above. Suborbital broad, and naked, covering a
large portion of the cheek.

Scales on the body of a moderate size; too much injured and displaced
in this specimen to admit of the exact number being counted in a
longitudinal row; those on the lateral line, however, are all
perfect and present to within five rays of the end of the dorsal,
and up to that point they amount to thirty-one. The fins, so far as
can be judged from their present state, are on the whole very
similar to those of the other species; but the dorsal and anal
spines, especially the second anal spine, appear rather stronger
than those of the _C. Aurata_. Pectorals long and narrow, contained
about three times and three quarters in the entire length.

COLOUR.—“White, with four dark brown much interrupted bands, giving a
mottled appearance; head coloured with the same; top of the head,
ridge of the back, edges of the dorsal, caudal and ventral fins,
tinted with fine azure blue.”—D.

Habitat, Chatham Island, Galapagos Archipelago.

Mr. Darwin’s collection contains a single specimen of a species of _Chrysophrys_ from the Galapagos Archipelago, not in a sufficiently good state of preservation to admit of a very detailed description being given of it, but, nevertheless, evidently distinct from any that I can find recorded by authors. It appears to belong to Cuvier’s second section of this genus characterized by the absence of any large _oval_ molar behind the others, though the last two or three in the inner series above are of considerable size. It differs, however, from all those described in the “Histoire des Poissons,” in having the conical incisors more numerous, and but three rows of molars in the upper jaw. The specimen also is of sufficient size to lead to the belief, that it would not have acquired any additional ones by further growth. The _C. aculeata_ resembles it, indeed, in this last character, but independently of other differences, this species is said to have a reclined spine before the dorsal fin which is not present in the one here described.

Out of twenty-two species of this genus described in the “Histoire des Poissons,” only one is from the Pacific Ocean, whence the present species was brought. The greater number are from the Atlantic and Indian Oceans.

FAMILY—MÆNIDÆ.

1. GERRES GULA. _Cuv. et Val.?_

Gerres Gula, _Cuv. et Val._ Hist. des Poiss. tom. vi. p. 349.

FORM.—Greatest depth one-fourth of the entire length. Back but little
elevated. Space between the eyes flat, with a fovea in the middle,
which is prolonged in a channel nearly to the extremity of the
snout. Length of the head exceeding its depth by one-fourth, and
contained about three times and three quarters in the entire length.
So much of the maxillary as is visible is of an oval form, its
length being twice its breadth at its posterior extremity.
Suborbital with the lower margin very indistinctly notched, and not
denticulated. Eyes very large, their diameter contained twice and
three quarters in the length of the head. The two orifices of the
nostrils of nearly equal size. No denticulations on any of the
pieces of the gill-cover. A narrow band of very minute velutine
teeth in each jaw, those above hardly visible to the eye, but
sensible to the touch: none on the vomer, palatines, or tongue.

Dorsal with the first spine extremely short; the second has a small
piece broken off at the tip, but appears to have been about the same
length as the third, which last equals two-thirds of the depth of
the body; the fourth and fifth are a little shorter than the third;
the succeeding ones gradually decreasing, as in the other species of
this genus: all the spines are moderately slender, the anterior ones
slightly arcuate, with scarcely any appreciable difference in the
degree of stoutness in the first four. Anal with the first spine
extremely short; the second obviously stouter than any of the dorsal
spines, but much shorter, being only half the length of the second
dorsal spine, or one-third the depth of the body; the third spine is
a trifle longer than the second, but much slenderer. Caudal deeply
forked; the lobes worn at the tips in this specimen, but their
length, when perfect, probably about one-fourth, or somewhat less,
of the entire length of the fish. Pectorals narrow and pointed, a
little shorter than the head, and contained four and a half times in
the entire length; fifth ray longest. Ventrals a little behind the
pectorals, and not more than two-thirds their length, or scarcely so
much; the spine a little shorter than the soft rays, and of about
the same degree of stoutness as the dorsal spines. Elongated scale
in the axillæ of the ventrals about three-fourths the length of the
spine, of a narrow lanceolate form, ending in a very fine point.

D. 9/10; A. 3/7; C. 17, &c.; P. 14; V. 1/5.
Length 3 inc. 6 lines.

COLOUR.—Not noticed in the recent state. In spirits, it appears of a
uniform silvery, with the back and upper part of the sides inclining
to dusky olive: no bands or any particular markings: fins pale.

Habitat, Rio de Janeiro.

The species of this genus are numerous, and extremely similar to each other. Many of them appear to rest on characters taken simply from the relative lengths and degrees of stoutness of the dorsal and anal spines. This renders it extremely difficult to identify single specimens. Perhaps I am wrong in referring the one described above to the _G. Gula_ of Cuvier and Valenciennes; but it makes so near an approach to that species, that I hardly dare characterize it as distinct. It cannot be the _G. Aprion_ of those authors, which is closely allied to the _G. Gula_, and is found on the same coasts, since its teeth are so very much finer: the caudal also is not scaled. It is small, but Cuvier and Valenciennes state that none of their specimens of the _G. Gula_ exceed five inches. Mr. Darwin took it in a salt-water lake, Lagoa de Boacica, at Rio de Janeiro.

2. GERRES OYENA. _Cuv. et Val.?_

Gerres Oyena, _Cuv. et Val._ Hist. des Poiss. tom. vi. p. 355. Smaris Oyena, _Rüppell_, Atlas zu der Reise im Nörd. Afr. Zoologie; p. 11. tab. 3. fig. 2.

FORM.—Greatest depth contained rather more than three and a half times
in the entire length: the dorsal curve very regular. Profile above
the eyes a little concave. Length of the head exceeding its depth.
Maxillary as in the species last described. Suborbital with its
lower margin distinctly but not very deeply notched; not
denticulated. Diameter of the eye less than one-third the length of
the head. Posterior orifice of the nostrils twice the size of the
anterior one. No denticulations on any part of the head or
gill-cover. A narrow band of velutine teeth in each jaw, of about
the same length and degree of fineness above and below; but none on
the palate or tongue.

The dorsal commences in an exact vertical line with the insertion of
the ventrals: the anterior spines are a little arcuate; the first,
as in the other species of this genus, is extremely short; the
second and third in this specimen are broken at their extremities so
that their exact length cannot be ascertained, but the portion of
the second remaining (and of this spine apparently only a very small
piece is gone) nearly equals half the depth of the body; length of
the fourth spine which is perfect not quite equalling two-fifths of
the depth; fifth, sixth, and seventh spines gradually decreasing;
eighth and ninth scarcely shorter than the seventh: the second spine
is much compressed, and though obviously stronger than any of those
which follow, not nearly so stout as in many other species; its
breadth is not more than one-twelfth of its length. Anal commencing
in a line with the fourth soft ray of the dorsal; the second spine
compressed similarly to the second dorsal spine, and of about the
same degree of stoutness, but its length one-third less, being just
equal to one-third the depth of the body; the third spine scarcely
shorter than the second, but much slenderer; the soft rays gradually
decreasing from the first, which is a little shorter than the third
spine, to the last but one, the last itself slightly prolonged to
form a point backwards. Caudal forked nearly to its base; the lobes
much elongated; the upper one, which is a trifle longer than the
lower, contained rather more than three times and a half in the
entire length. Pectorals narrow and pointed, a little shorter than
the head, and contained not quite four times and a half in the
entire length; fifth and sixth rays longest. Ventrals attached a
little behind the pectorals, and not much more than half their
length; the spine about three-fourths the length of the soft rays,
and scarcely stouter than the third spine in the anal: the axillary
elongated scale three-fourths the length of the spine. The scales on
the body of this species are not materially different from those of
the _G. Plumieri_ described in the “Histoire des Poissons.”

B. 6; D. 9/10; A. 3/7; C. 17, &c.; P. 16; V. 1/5.
Length 7 inches.

COLOUR.—“White, silvery.”—D. The fins are yellowish; the membranes
here and there dotted with black: the lobes of the caudal are
bordered internally with dusky. I see no trace of the interrupted
longitudinal bands spoken of by Cuvier and Valenciennes, neither is
there any allusion to them in Mr. Darwin’s notes taken from the
recent fish.

Habitat, Keeling Island, Indian Ocean.

I do not feel confident as to this species being, any more than the last, identical with that to which I have referred it. It requires an inspection of a large number of specimens in order to ascertain the true value of characters. The present one agrees with what is stated of the _G. Oyena_ by Cuvier and Valenciennes, excepting that the second anal spine, which they represent as shorter than the second dorsal spine by one-half, is here shorter by one-third only: also, as mentioned above, there is no appearance of any longitudinal bands. There is no other species in the “Histoire des Poissons,” to which it approaches more closely. But comparing it with Rüppell’s figure, if this last be scrupulously exact, there are a few other differences besides those already alluded to. Thus the first anal spine in Mr. Darwin’s specimen appears shorter in relation to the second, and this last stouter as well as longer. Also the soft rays of this fin gradually decrease, giving a sloping direction to the margin, whereas in Rüppell’s figure, all the rays are nearly of the same length, and made equal to the second and third spines. The caudal lobes, likewise, appear longer in Mr. Darwin’s specimen. It must be left for others to determine whether these discrepancies are indicative of a specific difference or not. As regards the geographic range of the _G. Oyena_, I know not that there is any thing in this respect to render its identity with the species here described improbable. It inhabits the Red Sea; and is also said to be common at the Mauritius;—whence it may very possibly extend as far eastward as the Keeling Islands, where Mr. Darwin’s specimen was obtained.

The _Sparus erythrurus_ of Bloch (pl. 261) is so extremely unlike the present species both in form and colours, that, except on the authority of MM. Cuvier and Valenciennes, who state that they had seen Bloch’s original specimen, no one could have suspected that the figure had been intended for it.

FAMILY—CHÆTODONTIDÆ.

CHÆTODON SETIFER. _Bloch._

Chætodon setifer, _Bloch_, Ichth. pl. 425. fig. 1.
———— _Cuv. et Val._ Hist. des Poiss. tom. vii. p. 58.

FORM.—This species is one of those characterized by a prolongation of
a portion of the soft dorsal fin. In the present specimen it is the
sixth soft ray which is thus prolonged. The total length of this
ray, measured from the root, is half the entire length of the fish;
and that portion of it which exceeds the adjoining rays is rather
more than half. Although the preopercle can hardly be called
denticulated, yet there are some faint traces of rudimentary
denticulations at the lower angle. The general form, in all other
respects, agrees with the descriptions of Cuvier and other authors.

D. 13/24; A. 3/21; C. 17, and 6 short; P. 16, the first short; V. 1/5.
Length 6 inc. 3 lines.

COLOUR.—“Body pale, with narrow dark straight lines which form
network: across the eye a black band: posterior half of the body
bright orange: upper part of the prolongation of the dorsal fin
edged with black, and a round patch of the same.”—D. The black
ocellus extends from the fifth to the thirteenth ray of the soft
dorsal. There is no trace of the four red or yellow streaks said by
Cuvier and Valenciennes to cross the forehead from eye to eye; but
probably they are effaced by the action of the spirit.

_A second specimen_ only differs from the above in being smaller,
measuring in length not quite five inches; in having the fifth
(instead of sixth) ray in the soft dorsal prolonged; and in the
ocellus extending from the fifth to the tenth ray only. In the last
two respects it agrees better with the description in the ‘Histoire
des Poissons.’ The filamentous ray terminates in an extremely fine
hair, which leads me to think that the extreme portion of this ray
in the first specimen has been broken off.

Habitat, Keeling Island, Indian Ocean.

Mr. Darwin’s collection contains two individuals of this species procured on coral reefs at the Keeling Islands. As according to his notes made from the recent fish, the posterior half of the body is bright orange, Bloch’s figure may not be so much overcoloured as is supposed by Cuvier and Valenciennes, who state that he has represented of a bright red, what ought to be silvery grey and yellow ochre. Perhaps the colours may depend in some measure on the season. Mr. Darwin’s specimens were obtained in the month of April.

GENUS—STEGASTES.[24]. _Jen._

_Corpus oblongo-ovale, compressum. Caput obtusum. Os parvum, haud
protractile. Dentes maxillares omnes incisores, parvi, æquales,
contigui, uniseriati; palatini velutini, minuti. Ossa suborbitalia
denticulata. Preoperculum margine adscendenti levissimè denticulato.
Operculum inerme. Membrana branchialis quatuorradiata. Pinnæ
verticales squamis confertis ferè omnino obtectæ: dorsalis unica,
subæqualis, membranâ ad apices spinarum parum laciniatâ: ventrales
radio primo molli elongato. Linea lateralis sub terminationem
dorsalis interrupta. Squamæ rostri et verticis parvæ; operculi et
corporis magnæ, obliquè dispositæ; omnes levissimè ciliatæ._

This apparently new form will enter into none of the genera established by Cuvier and Valenciennes. The palatine teeth serve to detach it from the _Sciænidæ_, while this character, taken in connexion with the compressed body, and the extreme scaliness of the vertical fins, require that it should be arranged with the _Chætodontidæ_, or at least have a place in that large group to which Cuvier has given the name of _Squammipennes_. It belongs to the second tribe in that family characterized by cutting teeth; and it would seem most nearly allied to _Pimelepterus_, but it does not approach that genus very closely, and may at once be distinguished from it, by the teeth being without spurs behind, and the dorsal and anal fins being more scaly. From _Dipterodon_, the only other genus in that tribe, it may be known by its undivided dorsal, independently of other marked differences.

But though this genus requires to be arranged with the _Chætodontidæ_ on the grounds above mentioned, in all its other characters it comes much nearer that portion of the _Sciænidæ_ which have the lateral line terminating beneath the end of the dorsal fin; especially _Pomacentrus_, which it resembles in the general form of the head and body, denticulated suborbital and preopercle, unarmed opercle, four-rayed branchiostegous membrane, and in the size and mode of arrangement of the scales on the body. I am not aware that any species of _Pomacentrus_ have the dorsal and anal fins so completely covered with scales: but, according to Cuvier and Valenciennes, there is a species of _Glyphisodon_,[25] to which genus _Pomacentrus_ is closely allied, which has these fins almost as entirely scaled, as in the true _Squamipinnati_; and if so, there is nothing but the palatine teeth which of necessity demands the separation of this new genus from the _Sciænidæ_. These teeth can be distinctly felt upon the vomer, but I am not quite sure from the small size of the fish, and its mouth also being small, whether they exist on the palatines as well. It may be added that this genus shews further itself an affinity to _Glyphisodon_, in the filamentous prolongation of the first soft ray in the ventrals. This character is not, I believe, found in _Pomacentrus_.

In which ever family it is placed, it forms a beautiful connecting link between the two. It is from the Cape Verde Islands.

STEGASTES IMBRICATUS. _Jen._

PLATE IX. fig. 2.

FORM.—Oblong-oval; the body much compressed. Greatest depth rather
more than one-third of the entire length: head one-fourth of the
same. Snout short and obtuse; the profile rising very obliquely, and
forming with the dorsal line one continuous curve. The back is
sharp, and appears more elevated than it really is, in consequence
of the dorsal fin being thickly coated with scales, and scarcely
distinguishable from the body. Ventral line less convex than the
dorsal; the edge of the abdomen somewhat carinated between the
ventral and anal fins, but in advance of the former rounded. The
upper and under profile meet at the mouth at a right angle. Mouth
small, and scarcely at all protractile. Jaws equal; each with a
single row of cutting teeth, which are small, though rather larger
below than above, even and closely set, forming a compact series: no
secondary teeth behind: vomer rough with minute velutine teeth. When
the mouth is closed, no portion of the maxillary is concealed by the
suborbital. Eyes round, moderately large, their diameter rather less
than one-third the length of the head, placed high in the cheeks,
and nearer the end of the snout than the posterior angle of the
opercle, the distance from the former being rather less than one
diameter. The nostrils consist of a single minute round aperture,
about half-way between the eye and the anterior margin of the
suborbital. The suborbital has its margin entire as far as the end
of the maxillary, at which point it curves backwards and upwards to
form a narrow band beneath the eye, and the lower margin of this
band is denticulated. The preopercle is likewise denticulated; but
the denticulations, which are principally confined to the ascending
margin, are not very obvious, and more readily felt than seen: the
angle at bottom is rounded, and rather exceeds a right angle; a
vertical from the angle would form a tangent to the posterior edge
of the orbit: the ascending margin is not quite straight, bending
slightly inwards a little below the middle. The opercle terminates
posteriorly in a very obtuse angle, and shows some indication of two
very minute flattened points, which, however, do not project beyond
the membrane: from the lowermost of these points the margin of the
subopercle passes obliquely forwards to form a continuous curve with
that of the interopercle, which is tolerably well developed.
Gill-opening of moderate size: the branchial membrane, which
apparently has only four rays, has a shallow notch in front, and
passes continuously from one side to the other, without being
attached to the isthmus.

The lateral line commences at the upper angle of the opercle, and,
inclining upwards, runs parallel, not to the dorsal line which can
hardly be distinguished, but to the upper edge of the dorsal fin,
its distance from which is contained about three times and a half in
the entire depth; it terminates a little before the termination of
that fin. Cranium, snout, cheeks, pieces of the opercle, the body,
and all the vertical fins, covered with finely ciliated scales;
those on the crown and snout small, but those on the opercle and
body large; the latter arranged in oblique rows; about twenty-seven
in a longitudinal line from the gill to the caudal, and about
fourteen in a vertical one from the dorsal to the ventral line: a
scale taken from the row beneath the lateral line, and about the
middle of the body, is of an oblong form, its breadth exceeding its
length, with the free edge dotted and finely ciliated, the basal
margin rather deeply crenated, the crenations separated by seven
striæ, which are carried on for only a short way, and do not
converge to a fan. The scales on the dorsal and anal fins are small
and closely compacted; those on the former arranged obliquely, but
the line of obliquity is in the opposite direction to what it is on
the body.

The dorsal fin commences in a line with the posterior angle of the
opercle, and occupies a space equalling half the entire length: the
height of the spinous portion is nearly uniform, but slightly
increases backwards; between the tips of the spines, the membrane is
a little jagged: the soft portion is scarcely more than one-third
the spinous in length, but is somewhat higher, terminating upwards
in an acute angle; the longest of the soft rays is about half the
depth of the body, the dorsal fin itself not included. The anal
answers to the soft portion of the dorsal, which it exactly
resembles; it has two spines in front, the first of which is very
short, and scarcely more than one-third the length of the second,
which itself is shorter than the soft rays; the second spine is
stouter than any of the dorsal spines. These two fins terminate in
the same vertical line. The caudal appears to have been square, but
the rays are worn at the tips, so that its exact form cannot be
ascertained; it is coated with scales for four-fifths of its length
from the base. Between the dorsal and the caudal fins is a space
equalling not quite one-third the depth of the body. Pectorals
attached a little behind the opercle, and a little below the middle;
slightly pointed; about the length of the head or rather shorter;
the first ray only half the length of the second; fourth and fifth
longest; all the rays, with the exception of the first two and the
last two or three, branched. Ventrals attached a little further back
than the pectorals; the first soft ray prolonged into a filament
reaching to the commencement of the anal; the spine is about half
the length of the filamentous ray, and about two-thirds that of the
second soft ray. Between these fins is an oval lanceolate scale
about one-third their length; and in their axillæ another elongated
one, narrower and more pointed than the former, and rather exceeding
it in length.

B. 4; D. 12/16; A. 2/12; C. 15, and 4 short; P. 21; V. 1/5.
Length 3 inches.

COLOUR.—Not noticed in the recent state. _In spirits_, the whole fish,
fins included, appears of a uniform dark brown.

Habitat, Porto Praya, Cape Verde Islands.

The only specimen of this new genus which exists in the collection was taken by Mr. Darwin off Quail Island, in the bay of Porto Praya. It is small, but probably full-sized, or nearly so; since the greater part of the species of _Pomacentrus_, to which genus it is so strongly allied, average about the same dimensions. Possibly some of the generic characters, which I have given above, may prove hereafter to be merely specific; but till other species shall have been discovered, their exact value cannot be ascertained.

FAMILY.—SCOMBRIDÆ.

GENUS—PAROPSIS. _Jen._