342 SMITHSONIAN MISCELLANEOUS COLLECTIONS [voL. 48 
The study of the nuclear shell had afforded valuable data ; to these 
must now be added the general features of the anatomy ; the presence 
or absence of a cecum to the cesophagus; the characters of the 
radula; of the verge, or external male organ; and the presence or 
absence of an operculum. The greater or less expansion of the 
mantle-edge over the shell has long been known to distinguish 
certain groups. It is probable that, when known, the characters of 
the ovicapsule will prove to have a certain value. I have been able 
to determine the characters of the radula in a number of species 
where it had not been known, and its absence entirely in the genera 
Aurinia and Maculopeplum; I have also been able to examine the 
verge in a number of species and find it to exhibit features which 
prove to have a systematic value not less than specific, and perhaps 
in some cases of even greater weight. It is a little remarkable that 
more attention has not been paid to the details of structure in this 
organ. 
In general, in the Volutide the external characters of the animal 
include a short rather blunt foot which, in the genera Voluta and 
Lyria, carries a small oblong operculum which is absent in all the 
other groups of which the animal is known. The nucleus of the 
operculum is terminal or subterminal. The head is wide, provided 
with short, rather stout, pointed tentacles which at their bases rise 
from large, rounded flaps or lappets. These lappets are sometimes 
continuous in front between the tentacles and sometimes separated 
partly or entirely by a deep median sinus. In other forms there is 
a sinus at the root of each tentacle with a wide, more or less auricu- 
late lappet between the tentacles in addition to the two lateral 
lappets. In the Volutomitrine there are no lappets at all, the eyes 
being situated on the apex of a tentacular projection extending 
parallel with the true tentacle and soldered to it for about one-third 
of its length. In the case of Tractolira and some other abyssal forms 
the eyes are wholly absent, but in the great majority of Volutes 
they are situated on the flat surface near the anterior edge of the 
lateral lappets, and are not raised above that surface. The verge 
is situated behind the right lappet and as in many other Proso- 
branchs is, when at rest, bent backward under the mantle. There 
is usually an appendix or supplementary smaller projection near the 
distal end which may assume various shapes. In many species the 
verge is bent upon itself when at rest, forming a blunt angle like 
an elbow, in others the whole organ projects backward from its 
root; in V. vespertilio the whole mass of the organ projects for- 
ward and is soldered to the nuchal surface, only the appendix (which 
