ZOOLOGY OF TH E VOYAGE OF TH E BEAGLE.
reach, according to Valenciennes, to the gill-opening, if not heyond it, here
only attain to heneath the m iddle of the eye ; and this character is invariable in five
specimens which Mr. D arw in has brought home. Judging from the description,
there would seem to he one or two further differences : the profile appears to he
more rectilineal, the pectoral spine shorter, and smoother on its external margin.
T he colours are on the whole similar, but the pectorals and ventrals darker : the
latter, which are said to he yellow in the C. punctatus, are here quite dusky in
every one of the specimens.
T he exact locality in South A m erica in which ]Mr. Darwin obtained this
species is uncertain, as the specim ens have lost their attached labels.
F am ily .—C Y P R IN ID Æ .
1. P oe c ilia u n im aculata. Val.
Pcecilia wnimaciilata, Yal. in Humb. Zool. et Anat. Comp, vol.ii. p. 158. pi. 51. fig. 2.
PoRM. Body oval, slightly elongated, thick anteriorly, compressed behind. T he dorsal and
ventral lines meeting at the m outh at an acute angle ; but tbe head, when viewed from above,
broad, and very much flattened between the eyes, and the snout obtuse. Greatest depth
about one-fourth of tbe entire length: thickness two-thirds of the depth. L ength of tbe bead
nearly equalling, or a little less than, tbe depth of tbe body. M outh small : jaws very protractile
; each with a single row of very fine, close-set, pointed teeth ; the lower one a trifle tbe
longest. Eyes large, tbeir diam eter three and a half times in the length o f the head, high in
the cheeks, reaching to the line of tbe profile. Nostrils consisting of one small orifice a little
above and rather in advance of the eyes.
Scales large, investing tbe head and all the pieces of the gill-cover, though very thin and
transparent on the opercle and not very obvious there. O n tbe body there are about eight in
the depth, and twenty-seven or tw enty-eight in a longitudinal row from the gill-opening to the
caudal. One taken from the middle o f 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. L ateral line very faintly marked out by a dotted line,
scarcely obvious in some places.
Dorsal small, commencing exactly at the middle point o f tbe entire length, measuring this
last quite to tbe extrem ity o f the caudal. A nal similar and opposite; in strictness, however,
term inating a very little in advance. T h e 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 tbe length of the bead ; 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.
L ength 2 inches.