permatozoa;--thus, in the thorax and mouth opening throughout their
whole width into the cavity of the peduncle, that is, homologically into
the anterior part of the head, and in the viscera being there lodged
instead of in the thorax and prosoma, there is a manifest resemblance to
the larva in its last stage of development: the absence of a
probosciformed penis, the spineless peduncle, the food being obtained
without the aid of cirri, and the length of the rectum, are likewise
embryonic characters. Not only are these males, as just remarked,
Cirripedia; but they manifestly belong to the Pedunculated Family. If a
specimen had been brought to me to class, without relation to its sexual
characters, I should have placed it, without any hesitation, next to the
genus Ibla; if the mouth alone had been brought, I should assuredly have
placed it actually in the genus Ibla: for let it be observed how nearly
all the parts resemble those of _Ibla Cumingii_, excepting only in size
and in being less hairy. The trophi are arranged in the same peculiar
position as in the female; the labrum is largely bullate, without teeth
on the crest; the palpi, though relatively smaller, are of the same
shape; so are the mandibles; the maxillae are more rounded and less
prominent, but have the same exact size relatively to the mandibles;
the outer maxillae have the same, quite peculiar pointed outline, and the
olfactory orifices are tubular, and hold the same unusual position. It
is most rare to find so close a resemblance in the parts of the mouth,
except in very closely allied genera, and often species of the same
natural genus differ more. Again, in the long oesophagus and constricted
stomach there is a resemblance to Ibla. In the male of _Ibla
quadrivalvis_, the caudal appendages are multi-articulate; now, this is
a character confined to four genera, namely, Ibla, Alepas, Pollicipes,
and Lithotrya. I may add, that large tubular olfactory orifices are
confined to the same genera, together with Scalpellum. Lastly, it
particularly deserves notice, that the prehensile antennae, in having a
hoof-like and pointed disc, with a single spine on the heel, much more
closely resemble these organs in Scalpellum, certainly the nearest ally
of Ibla, than in any other genus; they differ from the antennae in
Scalpellum, only in the ultimate segment not having a notch on one side.
These organs, unfortunately for the sake of comparison, were not found
in the female