Chapter VII: Part 7

FORM.—Head very large, broad and depressed, exactly one-fourth of the
entire length; its breadth two-thirds of its own length. Body
compressed posteriorly, with its greatest depth about one-sixth of
the entire length. Snout blunt and rounded, the lower jaw
projecting; gape wide. The teeth above form but a single row along
the intermaxillary, mostly small, but sharp, and the posterior ones
much curved: along each palatine there is a row of much stronger
ones, and at each angle of the vomer are two very long hooked ones,
resembling true canines. In the lower jaw the teeth are in a single
row at the sides, but in two or three rows in front, and are
unequally sized, some of the lateral ones being as strong as those
on each side of the vomer, and much hooked, as well as partially
reclining backwards. Tongue smooth, and free at the tip, which is
bluntish. Pharynx armed with two patches of velutine teeth above and
below. No regular barbule at the chin, but a row of minute cutaneous
cirri running all round the edge of the lower jaw; a similar row
along the anterior edge of the upper jaw, behind the intermaxillary,
with two thicker and more conspicuous appendages of the skin in the
middle. Eyes far apart, and not very large. Opercle armed with one
very strong spine, but only just the point appearing through the
skin.

Two small spines in front of the dorsal, a little more backward than
the insertion of the pectorals, the first very minute, and hardly
appearing through the skin. Second or true dorsal very long,
reaching to the base of the caudal, and of nearly uniform height
throughout, equalling about one-third of the greatest depth of the
body; the rays branched, and the membrane notched between their
tips. Anal commencing under the fifth dorsal ray, similar to that
fin, but with the membrane more notched between the rays: both
fins are fastened down at their extremities to the fleshy part of
the tail by a membrane. Caudal slightly rounded, when spread.
Pectorals broad and large, but, from the middle rays being
longest, appearing somewhat wedge-shaped, not quite equalling the
length of the head. Ventrals much smaller, only half their length,
and cut nearly square.

Skin perfectly naked. The lines of pores, which are very numerous
about the head and body, run in the exact directions laid down by
Cuvier and Valenciennes, in their description of the _B.
porosissimus_; but in addition to those which have been pointed
out by them, there is one commencing at the nostrils, and passing
underneath each eye, thence ascending a little behind the eye to
descend again by the margin of the preopercle; another directed
transversely across the cheek, connecting the former with the row
that passes along the edge of the lower jaw: this transverse row,
if continued upwards, would form a tangent to the posterior part
of the orbit. All the lines of pores are furnished with very
minute cutaneous appendages, similar to those already spoken of
above, as fringing the edges of the jaws.

D. 2—36; A. 33; C. 12, &c.; P. 20: V. ½.
Length 9 inches.

COLOUR.—“Above purple-coppery; sides pearly; beneath yellowish, with
silver dots in regular figures; iris coppery.”—D. The silver dots
alluded to by Mr. Darwin, are the lines of pores. There are two
longitudinal dark lines on the dorsal, the uppermost serving as an
edging: the anal also is edged in the same manner, especially
posteriorly.

Habitat, Bahia Blanca.

This species was found by Mr. Darwin cast up on the beach at Bahia Blanca, where he states that it is not uncommon. It approaches so closely the _B. porosissimus_ of Cuvier and Valenciennes, that I dare not consider it as distinct without comparison. Yet it differs from their description of that species, in having four vomerine teeth, instead of two; in having six more rays in the anal fin; and in having the additional lines of pores above indicated; though these last may have been accidentally left unnoticed. It requires the examination of more specimens to determine whether these differences result from a difference in species or not.

FAMILY.—LABRIDÆ.

COSSYPHUS DARWINI. _Jen._

PLATE XX.

_C. corpore elongato-ovali; capite grandi, fronte elevato, rostro ex
hoc declivi: caninis quatuor fortibus ad apicem utriusque maxillæ,
ad angulos oris nullis; dentibus lateralibus conicis; interiùs, ad
latera palati, granis plurimis minutis obtusis: preoperculo, limbo
excepto, operculo, et interoperculo, squamatis; preoperculo margine
integro: rostro, maxillis, et suborbitalibus ante oculos, nudis:
lineâ laterali subrectâ: pinnâ dorsali parte spinosa humili, spinis
ad apices laciniatis; molli, heic respondente anali, duplò altiore,
sub-acuminatâ: caudali æquali, solùm radiis exterioribus aliis paulo
longioribus._

D. 12/10; A. 3/12; C. 14, &c.; P. 17; V. 1/5.
LONG. unc. 19.

_Fish Pl. 20._

_Cossuphus Darwini. ½ Nat. Size._
]

FORM.—Head large: body of a suboval form, but much elongated: greatest
depth at the nape contained about four times and three quarters in
the entire length: head not quite three times and three quarters in
the same. Nape and forehead high, whence the profile descends
obliquely in a straight line to the end of the snout. Jaws equal,
and rather acute: lips fleshy: the end of the maxillary not quite
reaching to a vertical line from the anterior margin of the orbit.
Four very conspicuous, strong, curved, canine teeth at the anterior
extremity of each jaw; those above of nearly equal length, but the
two middle ones rather longer and stouter than the other two; of
those below, on the contrary, the outer ones are the longest, as
well as strongest, being nearly twice as much developed as the
middle ones, which last are of about the same length as, but rather
slenderer than, the outer ones above. The teeth at the sides of the
jaw are short and conical, and not very sharp pointed, forming a
regular series; below they amount to nine or ten on each side;
above, the series may have been originally of the same number, but
in this specimen several appear wanting. Besides these conical teeth
at the sides of the jaws, there is an inner band of small rounded
grains about the size of pins’ heads: the band is broader, and the
grains larger and more distinct above than below: many of them
appear much flattened, and as if ground down by use. Eyes of
moderate size; their diameter about one-seventh the length of the
head; rather high in the cheeks, and nearly equidistant from the end
of the snout and the posterior angle of the opercle. Snout and
suborbital in advance of the eyes, as well as the jaws, naked.
Preopercle large; occupying the posterior half of the cheek,
rectangular, but the angle at bottom much rounded, the ascending
margin vertical, both margins entire; covered with small scales; the
limb rather broad, bounded internally by a slightly raised ridge,
and without scales, but with a few scattered small pores. The
opercle and subopercle form together an irregular oblong, of which
the height is double the length; both are covered with scales larger
than those on the preopercle: the membrane terminates behind in a
blunt angle. The interopercle, which is very distinct, has three
rows of scales on its surface, but none on the margin.

The lateral line is nearly straight throughout its course, the bend
downwards beneath the termination of the dorsal fin being scarcely
perceptible. The tubes of which it is composed are unbranched;
many of them, however, incline upwards at their posterior
extremity towards the back. The scales on the body are rather
larger than those on the opercle: there appear to be upwards of
fifty in a longitudinal line. The free portion of each scale has
its surface finely granulated in the middle, and striated at the
sides.

The dorsal commences rather before one-third of the entire length,
excluding caudal, and occupies a space equalling nearly half the
same; the spinous portion is low, and the spines of nearly the
same length, the first and second only being rather shorter than
the succeeding ones; the membrane between the spines notched: the
soft portion rather pointed, and twice as much elevated as the
spinous. The anal commences beneath the eleventh or twelfth dorsal
spine, and terminates in the same vertical line with that fin; the
soft portion, which answers to the soft portion of the dorsal, is
preceded by three spines, increasing in length to the third, which
is double the first, though itself not above half the length of
the soft rays; these spines are not particularly stout. The space
between the anal and caudal equals one-sixth of the whole length.
Caudal rays nearly even, with the exception of the two outermost
above and below, which being rather longer than the others, give
the fin a slightly crescent-shaped form: the base of the caudal is
scaly, but the scales advance only a very little way between the
rays. Pectorals very little in advance of the ventrals, in length
more than half that of the head, with the second, third, and
fourth rays longest. Ventrals in an exact vertical line with the
commencement of the dorsal, nearly equal to the pectorals, with
the first and second soft rays longest; the spine rather more than
half the length of the first soft ray; the last soft ray united to
the body by a membrane.

COLOURS.—“Centre of each scale pale vermilion red: lower jaw quite
white: a large irregular patch above the pectoral bright yellow:
iris red, pupil blue-black.”—I. The dried skin in its present state
is of a nearly uniform brown.

Habitat, Chatham Island, Galapagos Archipelago.

I have named this species in honour of Mr. Darwin, whose researches in the Galapagos Archipelago, where he obtained it, have been so productive in bringing to light new forms. I have referred it to the genus _Cossyphus_ of Valenciennes, on account of the small rounded grains behind the principal teeth; but it rather departs from that group in not having the preopercle denticulated, and in having no scales on any of the vertical fins, with the exception of a few at the base of the caudal. In some respects it seems intermediate between that genus and _Labrus_. It does not appear to be described, though it seems to approach the _C. reticulatus_ of Valenciennes in many of its characters. That species however is from Japan.

The canines at the anterior extremity of each jaw are very conspicuous in this fish, and give it at first sight much the appearance of a _Dentex_.

CHEILIO RAMOSUS. _Jen._

_C. nigro-fuscus, infra lineam lateralem et in ventre obscurè
argenteus; pinnis pallidè fuscis immaculatis: corpore valde
elongato: dentibus in maxillâ superiore duobus anticis caninis
fortibus, lateralibus conicis parvis subœqualibus; in inferiore,
caninis parvis, lateralibus variis inæqualibus: lineâ laterali
ramosâ._

B. 6; D. 9/13; A. 3/12; C. 12, et 4 breviores; P. 11; V. 1/5.
LONG. unc. 9. lin. 6.

FORM.—Very much elongated, with the dorsal and ventral lines nearly
straight. Depth varying but little, and contained nine and a half
times in the entire length; thickness not quite three-fourths of the
depth. Head elongated, contained not more than three and a half
times in the entire length, compressed, with the cheeks vertical.
Snout very much produced, slightly rounded at the extremity: gape
reaching half-way to beneath the middle of the eye. Jaws scarcely
protractile; the upper one a little the longest: lips reflexed in
the form of membranaceous flaps, especially the lower one, the
margin of which is sinuous. Teeth ranged in a single row in each
jaw. Those above form a numerous, close-set, nearly even series at
the sides of the jaw, with two long hooked canines in front; the
lateral teeth amount to about thirty-five on each side, and are
small, but strong, somewhat conical, and not very sharp-pointed. In
the lower jaw there are two front canines, similar to those in the
upper, but much smaller; then follow four short conical teeth; then
six large triangular, compressed, sharp-pointed ones, but not all of
equal size; then five more small conical ones, which complete the
series on each side. No teeth on the vomer or palatines. Eyes of
moderate size, situate in the middle of the length of the head,
high, but not touching the line of the profile; their diameter
one-eighth the length of the head. Preopercle rectangular. Opercle
triangular, the membrane produced posteriorly at the upper part in
the form of a rounded angle: a short row of scales observable along
its upper margin, and another along its lower. Subopercle and
interopercle without scales. Also a short row of scales, similar to
those on the opercle, behind and partially beneath each eye, and,
with these exceptions, no other scales on the head. Above each eye
is an irregular row of minute pores: there are also pores beneath
the eye, and on the sides of the snout, mixed with short raised
lines having somewhat the appearance of written characters.
Gill-opening widely cleft; the branchial membrane free all round.

Scales on the body moderately large, and similar in form to those of
the _C. auratus_, as described by Cuvier and Valenciennes. The
number, in a longitudinal line from the gill to the caudal, is
forty-six, in a vertical about seventeen. Lateral line also as in
that species, but with the mucous tubes branched, and giving off
eight or nine twigs on each side.

The dorsal commences a little behind the terminating angle of the
opercle, and the anal immediately beneath the first branched ray
of the dorsal: these fins terminate in the same vertical line, and
the last ray in each is double: the simple rays are soft and
flexible. Caudal slightly rounded. Pectorals short, and obliquely
truncated, contained eleven and a half times in the entire length.
Ventrals very small, about two-thirds the length of the pectorals,
rounded, close together, with an elongated scale between them;
their point of insertion slightly backwarder than that of the
pectorals.

COLOUR.—Not noticed in the recent state. In spirits, it appears of an
almost uniform dark brown, at least above the lateral line. There is
some trace of a pale longitudinal band on each side of the head
beneath the eye, which is continued, but rather indistinctly, along
the whole length of the body, the tips of the scales remaining dark.
Possibly during life all the lower part of the sides and belly may
have exhibited numerous dark spots upon a pale or silvery ground.
Under part of the head pale brown, with some faintly-defined
ocellated spots: also a faint trace of red on the opercle. All the
fins pale brown, without spots.

Habitat, Japan?

This species was given to Mr. Darwin, when at Chiloe, by the surgeon of a whaling-ship, who said that he believed that it was caught in the Japan seas. From the great similarity which prevails amongst the species of this genus, I am not sure that it is really new, as I have ventured to consider it. The specific character also, so far as the colours are concerned, must be received with some caution, in consequence of these last not having been observed in the recent state. It seems to approach very closely the _C. hemichrysos_ of Cuvier and Valenciennes, brought by MM. Quoy and Gaimard from the Sandwich Islands; but it differs in its colours, especially in the fins being all uniformly pale brown, and in having fewer scales on the opercle, and beneath the eye. It is impossible to say, however, to what extent the colours may have been altered by the spirit: some of the scales also may have been rubbed off.

CHROMIS FACETUS. _Jen._

_C. supra virescenti-niger, lateribus pallidioribus: dorso modice
arcuato; fronte elevato, rostro summo ante oculos paululum excavato:
limbo preoperculi ports quatuor conspicuis impresso: squamis latis,
marginibus liberis levissime ciliatis: spinis dorsalibus quindecim,
analibus sex: pinnis ventralibus longe acuminatis, ad analem
pertingentibus: pinnâ caudali subæquali._

D. 1–5/10; A. 6/8; C. 16, &c.; P. 14; V. 1/5.
LONG. unc. 5. lin. 9.

FORM.—Oblong-oval, very much compressed; the back moderately elevated,
and more curved than the abdomen. Greatest depth a little behind the
insertion of the pectorals, and contained twice and three quarters
in the entire length: thickness about two-fifths of the depth.
Forehead high: profile falling very obliquely, and slightly hollowed
out in front of the eyes; the upper and under profile meeting at the
mouth at nearly a right angle. Head contained not quite four times
in the entire length; its own length and height nearly equal. Mouth
small, protractile: jaws about equal, the lower one, if anything, a
little the longest: lips not very fleshy. Maxillary rather slender,
retiring almost entirely, when the mouth is closed, beneath the
suborbital, the anterior margin of which is slightly hollowed out,
and somewhat sinuous. Teeth in card in both jaws, forming a narrow
band; the outermost row longer and stronger than the others,
especially the four or six middle ones in front, which are somewhat
conical and slightly hooked. Pharyngean teeth present, but none on
the vomer or palatines. Eyes rather small, their diameter about
one-fifth the length of the head; high in the cheeks, and a little
nearer to the snout than to the posterior margin of the opercle: the
space between broad, equalling nearly two diameters and a half.
Nostrils consisting of a single round orifice half-way between the
eye and the end of the snout. Preopercle with the basal margin
short, and forming a slightly obtuse angle with the ascending one,
the margin of which is entire. Opercle of a triangular form, broad
at top, but narrowing off towards the bottom. Subopercle and
interopercle much developed; their outer margins, taken together,
rounded off nearly in a semicircle. Branchial membrane quite free
all round, unattached to the isthmus, and but slightly emarginate.
Snout, suborbital, jaws, and limb of the preopercle, naked; but the
cheeks and rest of the opercular pieces scaly: the scales on the
subopercle large. Four large pores on the limb of the preopercle,
preceded by three others beneath the lower jaw: similar pores
beneath the eye, and extending partially round it; one on the crown
of the head, and a few smaller ones scattered about the snout; a
large one just above the opercle, and another higher up on each side
of the nape.

_Fish Pl. 21._

_Scarne Chlorid_
]

Scales on the body large; about twenty-five or twenty-six in a
longitudinal row, and eleven or twelve in the depth; broader than
long, with the free edges very minutely ciliated, the concealed
portions with a fan of thirteen striæ, and the basal margins with
twelve distinct crenatures. Lateral line interrupted; its first
portion at the depth of two and a half rows of scales beneath the
dorsal, and stopping beneath the commencement of the soft part of
that fin; recommencing three rows lower down, exactly in the middle
of the depth, whence it runs straight to the caudal.

Dorsal commencing above the opercle; the spinous portion of nearly
uniform height, and scarcely more than one-fifth of the depth; the
soft portion much higher, and terminating in a sharp point behind.
Anal answering to the posterior half of the dorsal, terminating
opposite to it, and similarly pointed; with six spines, which, as
well as the dorsal spines, are furnished with very conspicuous
filamentous tags. Caudal nearly even. Pectorals rounded, but not
very broad, their length rather more than three-fourths that of the
head; the rays rather slender. Ventrals pointed; the first soft ray
elongated, and reaching to the anal when laid back; the last ray
attached at its base by a membrane to the abdomen. Rows of small
scales between the rays of the caudal at the base of the fin; and a
few small ones along the base of the dorsal and anal, more
particularly on the soft portions.

COLOUR.—“Above, greenish black; the sides paler; slightly iridescent.”—D.—In spirits it appears of a nearly uniform brown all over, fins included.

Habitat, Maldonado, Rio Plata.

Mr. Darwin obtained this species at Maldonado, in a lake of fresh water, said sometimes to be a little brackish. It appears to belong to the genus _Chromis_ of Cuvier, placed by him amongst the _Labridæ_, but having evidently very strong affinities to some of the _Sciænidæ_. It differs essentially from the _C. Brasiliensis_ of Quoy and Gaimard,[32] in having six anal spines, and being destitute of all markings and spots. I am not aware that it is described by any author.

1. SCARUS CHLORODON. _Jen._
PLATE XXI.

_S. æruginoso cyaneus, capite et pinnis flavo-vittatis: maxillis
exteriùs lævibus, marginibus crenatis; caninis ad angulos oris
nullis: fronte gradatim proclivi: lineâ laterali tubis parum
ramosis: squamis ubique striato-granulatis: pectoralibus acuminatis,
radiis superioribus arcuatis: caudali radiis externis cæteris
longioribus, acuminatis._

D. 9/10; A. 3/9; C. 13. &c.; P. 15 vel 16; V. 1/5.
LONG. unc. 16.

FORM.—Of an oval form; the greatest depth one-third of the length,
caudal excluded: dorsal and ventral lines equally convex. Head a
little less than the depth of the body, not gibbous in front, but
with the profile falling regularly and gradually from the
commencement of the dorsal. Snout rather pointed. Jaws equal, their
outer surface smooth, but crenated on their cutting edges. No
spinous canines at the corners of the mouth. Eyes rather small,
their diameter not one-fifth the length of the head, situate above
the middle of the cheek, but equidistant from the posterior lobe of
the opercle and the extremity of the snout. Snout in front of the
eyes, and the lips, naked; but the cheeks and opercular pieces
covered with large scales, which form two rows on the cheeks.
Opercle terminating behind in a rounded angle. Scales on the body
very large; eight in the depth, and twenty-one or twenty-two in the
length: the entire exposed portion of each scale scabrous with
granulations, which are partially disposed in lines towards the free
edges. No scales on the vertical fins. The lateral line occupies the
second row of scales from the top, till it reaches a little beyond
the end of the dorsal, where it becomes interrupted, recommencing in
the fourth row, which at this point is the third: tubal pores in
some places ramified, but the ramifications not very distinct.

The dorsal commences above the posterior lobe of the opercle, and is
of nearly uniform height throughout. The length of the rays in the
soft portion, which is slightly higher than the spinous, is not
quite one-third of the depth. The whole length of this fin is half
the entire length. The anal answers to the last half of the
dorsal, and terminates in the same line; the three spines are
slender, and the first very short. Caudal with the central portion
slightly convex, but the three outer rays above and below
prolonged into a point one-third the length of the whole fin; the
lower point a little longer than the upper. Pectorals about
one-fifth of the entire length, pointed, with the upper rays
arcuate. Ventrals immediately beneath them, one-third shorter.

COLOUR.—“Fine verditer blue, with some yellow stripes about the head
and fins.”—D.—The dried skin is nearly of a uniform brown, but the
snout and cheeks are much varied with green: the jaws also are
green. A bright green patch in front of the eye, immediately beneath
which is a pale frænum, probably yellow in the recent state. Dorsal
and anal green: the former shews some trace of a lighter narrow band
running longitudinally below the upper edge of the fin; the latter
exhibits a very distinct fascia running along the middle. Caudal
pale green, with the upper and lower edges of a much deeper tint.
Ventrals in like manner edged with green. Pectorals wholly dusky.

Habitat, Keeling Island, Indian Ocean.

In so extensive a genus as the present, and one in which so much general similarity prevails amongst the species, the task of determining whether any particular one has been described before is extremely difficult. I can only say that the species which I have here ventured to characterize as new has been carefully compared with the descriptions of all those noticed in the “Histoire des Poissons,” and though there are several to which it is nearly allied, there is none to which it can be referred with certainty. It seems to approach nearest the _S. variegatus_, but that species is said to have the caudal square, by which I presume is meant that the upper and under rays are not prolonged into a point, as is the case in so many species of this genus, and in the one here described.

This species was taken by Mr. Darwin at the Keeling Islands.

2. SCARUS GLOBICEPS. _Cuv. et Val._

S. globiceps, _Cuv. et Val._ Hist. des Poiss. tom. xiv. p. 179.

FORM.—Oblong-oval, very much compressed throughout: the dorsal and
ventral lines nearly of equal curvature. Greatest depth contained
about three times and one-third in the entire length: thickness
twice and three-fifths in the depth. Head one-fourth of the entire
length, rather elevated at the nape, the forehead convex, whence the
profile descends nearly in the arc of a circle, giving the snout a
blunt and rounded appearance. The height of the head, taken in a
vertical line through the eyes, equals nearly but not quite its own
length. Mouth small, the gape not reaching half-way to the eye. Jaws
very slightly crenated on their cutting edges, the true teeth
appearing on the outer surface like minute scales. At the posterior
angle of each jaw, and on each side, are two sharp canines
projecting horizontally from the corners of the mouth, eight in all.
Eyes rather small, their diameter contained six and a half times in
the length of the head, situate a little above the middle of the
cheek, and a trifle nearer the extremity of the snout than the
posterior margin of the opercle. The nostrils consist of two minute
orifices a little in advance of the eye, and a little distant from
each other, the posterior one largest and kidney-shaped, the
anterior round and nearly closed by its membranous border. A cluster
of minute pores above and behind the eyes, and a few others
scattered about the snout.

Scales on the body very large, increasing in size at the base of the
caudal, where there are three very large ones covering the rays of
that fin for half their length or more: twenty-three in a
longitudinal line, and nine in the depth. Each scale of a roundish
form anteriorly, the basal portion with a projecting lobe in the
middle of the hinder margin, and with thirty-one striæ in the fan;
the exposed portion finely striated and granulated, with a broad
membranaceous border: those on the caudal nearly three times as
long as broad, but the ordinary ones with the length and breadth
nearly equal. Lateral line interrupted; the upper portion running
nearly straight at about one-fourth of the depth, till opposite
the end of the dorsal, where it inclines downwards: tubal pores
very distinctly ramified.

Dorsal very low, its height, in the middle of its length, being
scarcely more than one-eighth of the depth: the soft rays slightly
higher than the spinous, and increasing in length backwards. Anal
answering to the last half of the dorsal, and terminating in the
same line: three spines at its commencement not stouter than the
soft rays, the first very small. The last soft ray in both dorsal
and anal double. Caudal with the points about one-fourth of the
rest of its length; when spread, the interval is rectilineal, but
when the rays are closed the whole appears crescent-shaped.
Pectorals a little shorter than the head, of a somewhat triangular
form, the rays gradually decreasing in length from the uppermost
to the lowermost. Ventrals pointed, about two-thirds the length of
the pectorals, and immediately beneath them. A large oblong
lanceolate scale between the ventrals, nearly half their length:
also an oblong scale in the axilla of each, equalling the last of
the soft rays.

D. 9/10; A. 3/9; C. 13, &c.; P. 13; V. 1/5.
Length 11 inches.

COLOUR.—Not noticed in the recent state. In spirits, it appears bluish
grey on the back and sides with small round whitish spots, the
margin of each scale being defined by a purplish line; paler on the
belly: a white transverse line in front of the eyes passing from one
to the other; anterior part of the snout, mouth, cheeks, and lower
part of the head, yellowish white. Dorsal and anal pale, the former
with three narrow longitudinal purplish lines, the latter with one.
A portion of the under surface of the pectorals, extending from the
third to the fifth ray, and forming a longitudinal fascia, purple;
the rest of those fins, as well as the caudal and ventrals, pale or
nearly colourless.

Habitat, Tahiti.

This species was taken by Mr. Darwin at Tahiti. It so nearly answers to the description of the _S. globiceps_ of Valenciennes, brought by MM. Garnot and Lesson from the same locality, that I cannot suppose it to be distinct. This specimen, however, appears to have more spinous teeth at the corners of the mouth.

3. SCARUS LEPIDUS. _Jen._

_S. fuscus, capite et pinnis purpureo-cæruleo tinctis: fronte parum
elevato, æque ac rostro continue et gradatim proclivi; hoc apice
obtuso: maxillis exterius lævibus, marginibus vix crenatis; canino
ad angulum oris in maxillâ inferiore unico, in superiore nudo: lineâ
laterali distinctè ramosâ: pectoralibus subtriangulis: caudali
subæquali, radiis externis mediis vix longioribus._

D. 9/10; A. 3/9; C. 13, &c.; P. 13; V. 1/5.
LONG. unc. 8. lin. 7.

FORM.—General form not very dissimilar to that of the last species,
but the crown and nape less elevated, whence the profile falls in a
more gradual slope: snout, nevertheless, blunt at the extremity.
Depth of the body very nearly one-third of the entire length. Head
about one-fourth of the same. The height of the head is about
four-fifths of its own length. Jaws smooth externally, the true
teeth appearing like minute scales on their surface, the cutting
edges scarcely at all crenated: only one laterally projecting canine
at each corner of the lower jaw, none in the upper. Diameter of the
eye one-sixth of the head.

Dorsal not quite so low as in the last species; its height in the
middle of its length about one-seventh of the depth. Caudal nearly
even, the upper and lower rays being scarcely longer than the
others. Pectorals and ventrals similar, but the scale between the
latter shorter and more rounded. Scales on the body large, the
free portions finely striated and granulated, with a broad
membranaceous border: three large ones at the base of the caudal,
as in the last species. Lateral line distinctly branched, the
ramifications irregular and varying on each scale; in some
instances only one long stem extending nearly to the margin of the
scale, with one or more lateral twigs; in others, two, three, or
even four distinct stems, either simple or ramified.

COLOUR.—(_In spirits._) Of a nearly uniform dark brown, with some
faint traces of purplish blue about the head and fins, which
possibly may have pervaded some parts of the body also in the recent
state.

Habitat, Tahiti.

This species was taken with the last, and notwithstanding it presents two or three obvious differences in respect of form, as well as of colour, it is just possible it may be the same in a younger state. I think it not improbable that the points of the caudal may elongate with age, the forehead become more gibbous, and the spinous teeth more numerous. If it be distinct it would seem to be undescribed; though the colours not having been noticed in the recent state renders it difficult to speak with certainty on this point. For the same reason, the specific character may perhaps hereafter be found to require alteration.

4. SCARUS ——?

Mr. Darwin’s collection contains another species of _Scarus_ from the Keeling Islands, which may probably be distinct from all those hitherto noticed, but which being in rather a bad state of preservation, I shall content myself with describing as well as I can, without affixing any name to it, lest in the end it prove not new. Many of the species enumerated in the “Histoire des Poissons” having only their colours noticed, it requires that these should have been observed more in detail than what Mr. Darwin’s notes furnish in this instance, in order to decide whether it be identical or not with any of those spoken of in that work.

FORM.—A tolerably regular oval, somewhat attenuated at each extremity:
dorsal and ventral lines of equal curvature. Nape not at all
elevated, and the profile on the whole falling very regularly and
gradually from thence to the end of the snout, though there is a
slight eminence on the forehead. Depth one-fourth of the entire
length. Jaws smooth externally, but with the true teeth very
distinct upon their surface, and much more so upon their cutting
edges than in either of the last two species. One horizontally
projecting canine at each corner of the upper jaw, but none in the
lower. The terminating lobe of the opercle is slightly emarginated
behind, the membrane projecting immediately above the notch in the
form of a short salient point. Lateral line interrupted, the upper
portion nearly straight, and not inclining downwards at its
posterior extremity: the tubes very slightly ramified, and many of
them quite simple. The scales on the body are very finely granulated
and striated: there are no large ones at the base of the caudal.
Dorsal and anal low: height of the former contained four and a half
times in the depth of the body, and exactly equalling the distance
from the upper edge of the back to the lateral line. Pectorals
somewhat triangular, the uppermost ray of all a little arcuate.
Scale between the ventrals one-third the length of those fins.
Caudal slightly crescent-shaped, when the rays are closed: when
spread, all the middle rays appear even, the uppermost and lowermost
projecting very slightly beyond them.

D. 9/10; A. 3/9; C. 13, &c.; P. 14; V. 1/5.
Length 6 inches.

COLOUR.—“Body dull reddish and greenish, the colours being blended and
mottled: fins banded lengthwise with vermillion-red: head with
waving bright green lines.”—D.—No trace of bright colours remains in
its present state, and the only indication of markings is a narrow
crescent-shaped band across the middle of the caudal.

MALACOPTERYGII.

FAMILY. SILURIDÆ.

1. PIMELODUS GRACILIS. _Val._

Pimelodus gracilis, _Val._ in D’Orb. Voy. dans l’Amer. Mérid. Atl. Ichth. Pl. 2. fig. 5. ———— _Cuv. et Val._ Hist. des Poiss. tom. xv. p. 134.

FORM.—Of a slender elongated form, the body compressed behind the
dorsal. Greatest depth contained about seven and a half times in the
entire length: thickness at the commencement of the dorsal a little
less than the depth. Head, measured to the gill-opening, rather more
than one-sixth of the entire length: its breadth two-thirds of its
own length. Helmet smooth, and not very conspicuous, though with its
whole surface finely wrinkled: its breadth behind the eyes rather
more than one-third of its length, measuring this last from the end
of the snout to the further extremity of the interparietal process.
The solution of continuity extends back nearly to the base of the
process just mentioned, which last is narrow and lanceolate, three
times as long as broad at its base, but not reaching to the buckler,
or triangular plate in front of the dorsal, by one-third of its own
length. The buckler itself is not very large, but sufficiently
obvious.

Profile sloping gradually downwards in nearly a straight line from the
beginning of the dorsal to the end of the snout: this last depressed
and rounded horizontally in the form of a semicircle. Mouth wide,
but very little cleft, the commissure not reaching half-way to the
eye. Upper jaw projecting a very little beyond the lower. In each a
band of very fine velutine teeth; but none on the vomer or
palatines. Tongue smooth, and fastened down all round. Six barbules;
the maxillary pair very long, reaching to the commencement of the
anal fin; of the submandibular pairs, the exterior reach one-third
beyond the insertion of the pectorals; the interior are only half
the length of the exterior. Eyes round, of moderate size, their
diameter four and a half times in the length of the head, situate in
about the middle of the length: distance from one to the other one
diameter and a quarter. Lateral line nearly straight throughout its
course, dividing the body longitudinally into two nearly equal
portions.

Pectorals not quite equalling the length of the head, and a little
less than one-sixth of the entire length: the spine very little
shorter than the soft rays, very strong, with sharp teeth on its
inner edge, but the outer edge only granulated, or with a few slight
serratures towards the extremity. The humeral bone seen above the
pectoral projects backwards in the form of a spinous lamina, but
does not appear through the skin; it equals half the length of the
pectoral itself. The dorsal commences at one-fourth of the entire
length, and is of a somewhat rectangular form, the soft rays not
decreasing much backwards: its length equals four-fifths of the
depth of the body, and two-thirds of its own height. The spine is
not so strong as that of the pectoral, and with only a few small
serratures on the outer edge near the tip. The space between the
dorsal and the adipose a little exceeds the length of the former.
The adipose itself is twice the length of that fin; very low at
first, but gradually rising, until, before its termination, it
becomes equal to between one-half and one-third of the depth. The
vent is in the middle of the entire length, caudal excluded. Anal
short, and just beneath the middle of the adipose, there being about
one-fourth of this last fin in advance of it as well as behind it:
the first four rays simple, but apparently all articulated, the
first two or three very minute and not easily observed. Caudal
forked for two-thirds of its length: the upper lobe a little longer
than the lower, and contained five and a half times in the entire
length. Ventrals immediately beneath the last ray of the dorsal; a
little shorter than the pectorals, and not reaching to the anal by
half their own length.

D. 1/6; A. 14 or 15; C. 17, &c.; P. 1/9; V. 6.
Length 5 inches 2 lines.

COLOUR.—(_In spirits._) Brownish, inclining to silvery in some places:
a dusky fascia formed of dots along the lateral line. Dorsal rather
dusky at the base, and with the upper portion also dusky between the
rays: a dusky spot on the anterior part of the adipose.

Habitat, Rio de Janeiro.

This species was taken by Mr. Darwin in a running brook at Rio de Janiero. It approaches on the whole so nearly the _P. gracilis_ of D’Orbigny, that I can hardly suppose it to be distinct. Yet there are some slight differences observable in this specimen. It has more anal rays; the adipose appears shorter; and the upper lobe of the caudal is not so prolonged, though possibly it may be worn down. Also D’Orbigny’s figure appears to want the dusky stains on the dorsal and adipose fins. If it be not that species it must be new, as there is none other described by Cuvier and Valenciennes with which it will assimilate better.

2. PIMELODUS EXSUDANS. _Jen._

_P. corpore parum elongato, altitudine quintam partem longitudinis
æquante: galeâ lævi, inconspicuâ, processu interparietali haud
clypeum parvum prædorsalem attingente: poris paucis buccalibus
amplis, serie obliquâ dispositis: maxillis æqualibus: cirris sex;
maxillaribus haud analem attingentibus: lineâ laterali primum
deflexâ, deinde rectâ: pinnis dorsali et anali brevibus; adiposâ
dorsali haud duplo longiore: caudali profundè bifurcâ, lobis
æqualibus: spinâ pectorali margine interno fortiter dentato._

D. 1/7; A. 13 vel 14; C. 17, &c.; P. 1/8; V. 6.
LONG. unc. 3. lin. 6.

FORM.—In some respects resembling the last species, but the body much
less elongated, the depth and thickness remaining the same. The
depth is about one-fifth of the entire length; the head rather more
than one-fifth. The helmet is scarcely so much wrinkled, and the
interparietal process not so long, reaching only half-way to the
buckler, which last is smaller and less obvious. The solution of
continuity of the bones of the cranium appears to extend back in the
form of a narrow fissure nearly to the base of the interparietal
process, but is not very obvious, except between the eyes, where it
opens into a sort of elongated ellipse. There are eight or nine
pores on the top of the head, rather behind the eyes, so arranged as
to form nearly a complete circle. There is also a very conspicuous
row of three or four large oval pores on the cheek, at the anterior
part of the opercle, descending obliquely forwards: other smaller
ones may be seen scattered about different parts of the head. The
jaws are equal: the teeth as in the last species, excepting that a
roughness can be distinctly felt upon the vomer beneath the skin,
though there are no teeth on that part which appear through it. The
maxillary pair of barbules reach to a point midway between the
insertion of the ventrals and the commencement of the anal: of the
submandibular pairs, the exterior do not reach beyond the insertion
of the pectorals; the interior are two-thirds the length of these.
Eyes elliptical, the longitudinal diameter about one-fifth the
length of the head; situate nearer the end of the snout than the
posterior part of the opercle; the interval between them nearly two
diameters. The lateral line slopes downward till opposite the fourth
soft ray of the dorsal, then passes off straight along the middle to
the caudal.

The pectorals are contained about five and a half times in the entire
length. The spine is similar to that of the last species; but the
humeral bone is shorter, and scarcely one-third of the pectoral
itself. The dorsal is similar; and the space between it and the
adipose is the same; but the adipose itself, though of the same
form, is not so long, from the body being less elongated; it is not
more than half as long again as the dorsal. Anal similar, but the
adipose not advancing so much beyond it. Caudal and ventrals
similar; but the former with the lobes equal.

COLOUR.—(_In spirits._) On the whole similar to, but darker than that
of the last species. There is some appearance of a fascia along the
lateral line. The upper part of the dorsal, and also of the anal, is
dusky, but there is no spot on the adipose. Pectorals and ventrals
dusky.

A _second specimen_ differs from the above in no respect, except in
being smaller, measuring two inches and a quarter in length, and in
having one ray more in the anal.

Habitat, Rio de Janeiro?

The number annexed to this species has been lost, but there is reason for believing that Mr. Darwin took it with the last at Rio de Janeiro. I cannot identify it with any of those described by Cuvier and Valenciennes in the “Histoire des Poissons.”—It affords another instance of the indefiniteness of the character derived from the presence or absence of vomerine teeth; since a band of such teeth, which are considered by Valenciennes as absent in this genus, can be distinctly felt and made obvious by removing the skin of the palate, though they do not appear externally. This is not the case with the species last described, to which nevertheless, the present one approaches so closely in general character, that they never could be widely separated. Except for the greater elongation of the body in the _P. gracilis_, I should have been almost inclined to consider them as sexes of the same species.

CALLICHTHYS PALEATUS. _Jen._

_C. capite compresso lævi: ore parvo, cirris maxillaribus ad utrumque
angulum duobus, haud ultrà oculos pertingentibus; labro inferiore
reflexo, et in duos cirros breves membranaceos producto: spinâ
pectorali compressâ, forti, margine interno leviter dentato, externo
lævi, quintam partem totius longitudinis æquanti: caudali bifurcá,
lobis æqualibus acuminatis._

D. 1/7—1; A. 6; C. 14, &c.; P. 1/7; V. 6.
LONG. unc. 1. lin. 10.

FORM.—General form resembling that of the _C. punctatus_. Depth, at
the commencement of the dorsal, one-third of the length, excluding
caudal: thickness at the pectorals three-fourths of the depth. Head
slightly compressed, its height very little less than its length,
this last, measured to the gills, being rather less than one-fourth
of the entire length. Profile falling from the dorsal in one regular
slope, and nearly rectilineal till it arrives before the eyes, where
it curves downwards, making the extremity of the snout obtuse. Mouth
small, the upper jaw a little projecting; two maxillary cirri at
each angle; these nearly equal; the lower one a little the longest,
reaching to beneath the middle of the eye: also two short cirri,
only half the length of the maxillary ones, pendent from the
reflexed lower lip, a little separate from each other, one on each
side the middle. Teeth so minute as hardly to be distinguished; a
row can just be felt on each jaw, and on the vomer. Head smooth. The
number of dorsal laminæ twenty-one; that of the ventral twenty.

Pectorals a little exceeding the length of the head; the spine nearly
as long as the fin itself, but not exceeding one-fifth of the entire
length; very strong, compressed, and sharp-pointed, with a few fine
teeth or serratures on the inner margin, but smooth on the outer.
Height of the dorsal more than half the depth, and a little more
than its own length, this last equalling the space between it and
the adipose: the spine strong, and similar to that of the pectoral.
Anal directly underneath the adipose, and hardly occupying more
space. Ventrals shorter than the pectorals, attached beneath the
last third of those fins, or under the second soft ray in the
dorsal, and scarcely reaching more than half-way to the anal: the
first ray, as well as that of the anal, somewhat hispid. Caudal
forked for half its length, which about equals that of the head: the
lobes equal and pointed.

COLOUR.—(_In spirits._) General colour yellowish brown, with dusky
spots and mottlings: breast and edge of the abdomen whitish.
Pectorals, ventrals, and anal, almost wholly dusky: dorsal and
caudal spotted.

This species, in its general character, approaches so extremely near the _C. punctatus_ of Valenciennes, that perhaps I am in error in considering it distinct. But it is remarkable for possessing, in addition to the four usual maxillary cirri, two labial, which are neither represented in D’Orbigny’s figure,[33] nor noticed in the description given in the “Histoire des Poissons,” and which therefore I infer are not present in that species, as they could hardly have been overlooked, or been deemed unimportant to be noticed. The maxillary cirri also, which in the _C. punctatus_, reach, according to Valenciennes, to the gill-opening, if not beyond it, here only attain to beneath the middle of the eye; and this character is invariable in five specimens which Mr. Darwin has brought home. Judging from the description, there would seem to be one or two further differences: the profile appears to be more rectilineal, the pectoral spine shorter, and smoother on its external margin. The colours are on the whole similar, but the pectorals and ventrals darker: the latter, which are said to be yellow in the _C. punctatus_, are here quite dusky in every one of the specimens.

The exact locality in South America in which Mr. Darwin obtained this species is uncertain, as the specimens have lost their attached labels.

FAMILY.—CYPRINIDÆ.

1. PŒCILIA UNIMACULATA. _Val._

Pœcilia unimaculata, _Val._ in Humb. Zool. et Anat. Comp. vol. ii. p.
158. pl. 51. fig. 2.

FORM.—Body oval, slightly elongated, thick anteriorly, compressed
behind. The dorsal and ventral lines meeting at the month at an
acute angle; but the head, when viewed from above, broad, and very
much flattened between the eyes, and the snout obtuse. Greatest
depth about one-fourth of the entire length: thickness two-thirds of
the depth. Length of the head nearly equalling, or a little less
than, the depth of the body. Mouth small: jaws very protractile;
each with a single row of very fine, close-set, pointed teeth; the
lower one a trifle the longest. Eyes large, their diameter three and
a half times in the length of the head, high in the cheeks, reaching
to the line of the profile. Nostrils consisting of one small orifice
a little above and rather in advance of the eyes.

Scales large, investing the head and all the pieces of the gill-cover,
though very thin and transparent on the opercle and not very obvious
there. On the body there are about eight in the depth, and
twenty-seven or twenty-eight in a longitudinal row from the
gill-opening to the caudal. One taken from the middle of the side
found to be of a semi-elliptic form, the exposed portion marked with
numerous very fine curved concentric lines, the basal with sixteen
or seventeen deeper-cut nearly parallel striæ gradually lengthening
from the sides towards the middle, but not converging to a fan.
Lateral line very faintly marked out by a dotted line, scarcely
obvious in some places.

Dorsal small, commencing exactly at the middle point of the entire
length, measuring this last quite to the extremity of the caudal.
Anal similar and opposite; in strictness, however, terminating a
very little in advance. The last ray in both these fins double: the
first two in the anal short. Caudal rounded. Pectorals and ventrals
small and narrow, the former three-fourths the length of the head;
the latter not above half the same. The pectorals, when laid back,
reach to the insertion of the ventrals, but the ventrals hardly
reach to the commencement of the anal.

B. 5; D. 7; A. 9; C. about 24, including short ones; P. 14 or 15; V. 6.
Length 2 inches.

_Fish. Pl. 22._

_From Nature on Stone by W. Hawkins._
]

_N^o. 1. Pœcilia decem-maculata._ _Magnified View twice Natural Size._ _1a._ _Natural Size._ _2. Lebias lineata._ _Nat. Size._ _2a._ _Magnified View of Teeth._ _3. Lebias multidentata_ _Nat. Size._ _3a._ _Magnified View of Teeth._ _4. Mesites maculatus._ _Nat. Size._ _5. attenuates._ „

COLOUR.—Greenish-brown, with a conspicuous black spot on the middle of
each side, a little in advance of the commencement of the dorsal.
Dorsal a little dotted and mottled with dusky, especially towards
the tips of the rays. The other fins plain.

Habitat, Rio de Janeiro.

This species, which was discovered by Humboldt, was observed by Mr. Darwin in great numbers in fresh-water ditches at Rio de Janeiro: others were taken in equal plenty in a salt lagoon. The bellies of the females are very turgid when big with young, which are said to be excluded alive, and yellowish.—Valenciennes, in his description, speaks of the opercle as being smooth, or without scales, though he says the preopercle is covered with scales; and he would lead one to suppose that they are absent on this part in the whole genus, as it enters into his generic character; I find them, however, present, though very thin and transparent, both in this species and the next.

The general resemblance which _Pœcilia_ bears to _Mugil_, as regards the form of the head and mouth, is very striking, and calls up irresistibly the idea of some relation of analogy between these two genera.

2. PÆCILIS DECEM-MACULATA. _Jen._
PLATE XXII. Fig. 1.

_P. corpore subelongato, viridescenti-fusco; lateribus maculis nigris
circiter decem serie longitudinali dispositis; pinnis immaculatis:
dentibus subincisivis: caudali subtruncatà._

D. 8; A. 10; C. 22, brevibus inclusis; P. 9; V. 5.
LONG. unc. 1. lin. 4.

FORM.—More elongated than the last species; the snout not so acute
when viewed laterally. Depth not more than one-fifth of the entire
length, the length of the head being equal to it. Mouth and jaws
similar; the teeth also in one row in each jaw, and forming a
compact series, but more incisor-like than pointed, with oblique
cutting edges. Scales of a different form and sculpture; more oblong
than semi-elliptical, broader than long; the deep striæ behind more
numerous, amounting to twenty or more, and all drawn nearly of the
same length. They cover all the pieces of the opercle as in the _P.
unimaculata_.

Dorsal and anal exactly opposite, commencing at a point a little
anterior to the middle of the entire length, reckoning this to the
extremity of the caudal. Caudal rather more approaching to square
than rounded; the number of rays fewer than in the last species.
Pectorals narrower, having also fewer rays. Ventrals very small,
scarcely more than half the length of the pectorals. When laid back,
the pectorals reach to beyond the insertion of the ventrals: the
ventrals do not attain to the anal.

COLOUR.—Greenish-brown, with about ten conspicuous somewhat
oval-shaped dusky spots, arranged in a longitudinal line along the
middle of each side. All the fins plain.

Habitat, Maldonado.

This, which is evidently a new species of _Pœcilia_, was taken by Mr. Darwin at Maldonado, in a lake that had been suddenly drained. There are three specimens in the collection, none of them exceeding the length above given. Mr. Darwin, however, states in his notes, that he believes them to be full grown, having taken them so repeatedly, in brooks, of the same size. The number of spots varies from nine to twelve, and is sometimes different on the two sides of the same specimen.