PLATE XXII. Fig. 3.
_L. corpore subelongato, subcompresso, viridescenti-fusco; lateribus
fasciis angustis paucis longitudinalibus albidis obscurioribus:
dentibus seriebus plurimis dispositis, omnibus tricuspidatis:
caudali rotundatâ._
D. 9; A. 9; C. 26, brevibus inclusis; P. 13; V. 6.
LONG. unc. 3. lin. 2.
FORM.—The general form and proportions of this species are extremely
similar to those of the last; but it differs very remarkably in
having behind the anterior row of tricuspid teeth, a band of minuter
teeth above and below, all of which are also tricuspid, and
similarly formed to those in front. Head one-fifth of the entire
length; flattened on the crown. Jaws nearly equal; upper one very
protractile. Scales large; about thirty-two in a longitudinal line,
and eight in the depth; covering all the pieces of the opercle;
similar in form to those of the last species, but with the striæ on
the free portion finer and more numerous, the deep-cut basal striæ
also rather more numerous, amounting to about fourteen, and of
unequal lengths, gradually increasing from the outermost to the
middle ones. Lateral line similar; also the same pores on the lower
jaw. Fins and finray-formula similar: in both species the first and
last rays of the dorsal and anal are simple, and shorter than the
others. The anal perhaps terminates a little nearer the caudal than
the dorsal does.
COLOUR.—(_In spirits._) Greenish-brown, with very little appearance of
markings in its present state. There is, however, some indication of
an irregular scattered row of small black spots on each side, a
little below the ridge of the back; also of two or three pale
longitudinal narrow bands along the middle of the sides, which were
probably more conspicuous in the living fish. The belly is yellow,
and very tumid; but these are evidently characters merely indicative
of the female sex.
Habitat, Monte Video.
This is another new species of _Lebias_ taken by Mr. Darwin in
fresh-water at Monte Video, if indeed it strictly belong to the genus;
but the circumstance of the teeth being in several rows, and in fact
forming a complete band, is at variance with the generic characters as
given by Cuvier. The teeth however being exactly of the same form as in
the other species, and the general characters on the whole similar, I
have not thought it expedient to erect it into a new genus. There is but
one specimen in the collection, which appears to be a large female big
with young.