Mr. Darwin’s collection contains two new forms from South America,
closely allied to each other, yet forming distinct genera, and which
will not enter into any of those described by authors. At first it was
conceived that they were Malacopterygian fishes, more especially from
their having all the rays in the dorsal and anal fins articulated; and
to belong to the Apodal division of that group, from their being
supposed to be without ventrals; but, on a closer inspection, the
ventrals, which are very small, were found to have been overlooked, and
it was evident altogether that the true place of these fishes in the
system was amongst the _Blennidæ_. The mention of this circumstance will
explain why they were omitted to be noticed in their proper place.
These two genera, so far as can be judged from the situations in which
Mr. Darwin obtained them, have the same habits as the Blennies, lurking
under stones and weeds; and I propose to give them respectively the
names of _Iluocœtes_ and _Phucocœtes_.