f the natural size at _a_ fig. 4. The capitulum is
43/1000ths of an inch, measured across the scuta and terga; and the same
measured from the base of the carina to the top of the capitulum; hence
it is broader, by a quarter of the above measurement, and considerably
higher than the male of _S. Peronii_. From the capitulum being higher,
that is, not so much truncated, the orifice is placed more obliquely.
The membrane connecting the valves is finely villose, and is besides
furnished with spines, conspicuously thicker and longer than those on
the male _S. Peronii_. The scuta and terga are much more elongated, a
scutum being here 35/1000ths of an inch in length. The carina descends
only just below the basal points of the terga, instead of far below
them. The rostrum is a little broader and more arched than the carina;
it is 2/1000ths in length, and therefore more than two thirds of the
length of the carina, the latter being 28/1000ths of an inch from the
apex to the basal margin. The primordial valves, with the usual
hexagonal tissue, are seated on the tips of the scuta, terga, and
carina, but not on the rostrum; so that these valves follow the same law
of development, as in the ordinary and hermaphrodite form of Scalpellum.
The scuta (_a_, fig. 4, greatly enlarged), the terga (_b_), and carina
(_c_) of the male, resemble the same valves in the hermaphrodite, much
more closely than do these valves in the male and hermaphrodite _S.
Peronii_. The rostrum has not its basal margin hollowed out, and is very
much larger relatively to the carina, than in the hermaphrodite. The
large relative size of the rostrum in the complemental male both of this
species and of _S. Peronii_, is a remarkable character, which I can in
no way account for.

The peduncle is narrow and short, but in a different degree in the two
specimens examined. It is naked. The prehensile antennae were not in a
good state of preservation: the disc is narrower than the basal segment,
and only slightly pointed, in which important respect it differs from
the same part in the foregoing species; at its distal end, rather on the
inner side, there are two or three spines, apparently in place of the
excessively minute hairs, which are found at the same spot in some or in
all the other species of Scalpellum, and in Ibla: similar strong spines
occur in Pollicipes. Unfortunately, for the sake of comparison, I was
not able to find the prehensile antennae in the hermaphrodite