HE NAUTILUS. 3 
The oral disk is entire, but is slightly indented in the median line 
below a furrow running up toward the mouth. 
The cephalic tentacles are very stout and large, very elongate- 
conical, with moderately pointed tips. They are situated above, and 
not, as in most Trochid@, on each side of the muzzle. Their inner 
bases are connate, and there is no intertentacular “veil,” or any 
tubercular traces thereof. 
The eyes are large, strongly pigmented, ovoid, and sessile on the 
outer bases of the tentacles, or perhaps I should say, just by the outer 
bases, They are not pedunculate or elevated on pedicels in any of 
the specimens examined, and I am quite confident that this is not 
caused by the contraction due to alcohol, but is normal to the species. 
The epipodial apparatus is complicated, and exhibits a certain . 
amount of variation between different individuals in the situation 
and number of its processes. In the males, it is subjected to a re- 
markable modification for sexual purposes. The epipodium begins 
immediately behind the eye and a trifle below it. In the females it 
is produced into a large broadly linguiform process, half as long as 
the cephalic tentacles and fringed with close-set uniform small pointed 
papillze or filaments. This process exists in the male on the left side. 
The posterior margin then curves in toward the side of the foot; it 
becomes quite narrow and shows two lateral tentacles of moderate 
size; then a vacant space ; then at the front edge of the operculum 
two or three filaments, small, but larger than any in the vacant 
space ; then another, but larger one; and finally another, which is 
behind the middle of the operculum, and is the last on that side. 
The epipodial line is continued to the end of the foot, the dorsal sur- 
face above it, being transversely rugose and with a linear median 
furrow. On the other (right) side we find a small, a large, two sub- 
equal small, another large filament, followed by a slight gap and 
then by a still larger tentacular process. The flap which corresponds 
to the fringed process on the left side, is remarkably modified in 
the male. 
Behind, and close to the right eye, is a small tubular, longitudi- 
nally striate, cylindrical verge, not exceeding (in alcohol) two mill- 
imetres in length. Below it the epipodial flap is enormously pro- 
duced, and its front edge is rolled backward upon itself, forming a 
tube into the proximal opening of which the end of the verge may 
project. The flap is rolled so that it makes nearly two layers, and 
thus a very capable cylinder, which, when unrolled and released, 
