the inferior point very sharp and small, so that there
is one less tooth than in the hermaphrodite. The maxillae have two or
three large upper spines, the others being very thin; I believe the
lower part is upraised and step-like, as in the hermaphrodite. The
outer maxillae are bilobed in front, with a few short bristles on the
outer side near the bottom. I was not able, from the dried state of the
specimens, to discover whether the olfactory orifices were tubular.
Altogether it was apparent, from this imperfect examination, that there
was a close similarity between the mouth of the parasite and of the
hermaphrodite.

The _Thorax_ is unusually elongated.

_Cirri._--The first pair is very short, and is distant from the second.
All have the appearance of immaturity, with their pedicels very long in
proportion to their rami; the latter are slightly unequal in length,
even in the sixth pair. There appeared to be six segments in the rami of
the sixth pair, each segment bearing two or three pair of long spines.

_Caudal Appendages_, with two or three little spines on their summits.

_Penis_, short, blunt, thick at the apex, with one or two spines on it.
I did not see any ovaria, but this could hardly have been expected in
specimens in a dried condition, without they had happened to have been
in a gorged condition. Certainly there were no ova.

In the general summary at the end of the genus, I shall give my reasons
for believing this parasite to be the Complemental Male of the
_Scalpellum rostratum_.

5. SCALPELLUM PERONII. Pl. VI, fig. 6.

SMILIUM PERONII. _J. E. Gray._ Annals of Philosoph., new series,
tom. x, 1825.

---- ---- . . . . . Spicilegia Zoologica, tab. iii, fig. 10, 1830.

ANATIFA OBLIQUA. _Quoy_ et _Gaimard_. Voyage de l'Astrolabe, Pl.
xciii, fig. 16, 1823-1834.

POLLICIPES OBLIQUA. _Lamarck._ An. sans Vertebres (2d edition).

_S. (Herm.) valvis 13: laterum paribus tribus; pari superiore multum
elongato: pedunculi squamis calcareis nullis._

(Herm.) Capitulum with 13 valves: three pair of latera; upper latera
much elongated: peduncle without calcareous scales.

Mandibles with 10 or 11 unequal teeth: maxillae with the edge nearly
straight, bearing numerous spines.

COMPLEMENTAL MALE, attached externally, between the scuta and below the
adductor muscle; pedunculated; capitulum formed of six valves, with the
carina descending far beneath the basal angle of the terga; mouth