Batrachus porosissimus, _Cuv. et Val._ Hist. des Poiss. tom. xii. p.
373.
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.