38 
d. Neptunellina. Operculum ovate ; nucleus central. MNeptunella 
(cutaceum). 
The teeth of this family have been verified in a dozen species. 
Fam. 12. Scyroryrip#. Head produced, conical ; tentacles very 
small; foot small; siphon of mantle produced; operculum none. 
Scytotypus *. 
Fam. 13. Vexutinip. Head truncated; tentacles and foot 
moderate, rounded; mantle edge inflated, folded on the edge into 
two canals ; eyes on outer side of tentacles ; operculum none (fig. 10). 
Velutina, Marsenina. 
TN Kf - 
Fig. 10.— Velutina haliotidea. 
Fam. 14. Naricip#. Head truncated; tentacles moderate ; foot 
very large, much-produced; shell sunk into the foot; eyes none ; 
operculum distinct, spiral, few-whorled (fig. 11). 
Fig. 1]1.—Natica pulchella. 
a. Operculum, outer layer shelly. Natica. 
6. Operculum simple, horny. Neverita, Polinices, Mammilla, Sto- 
mata. 
From Dr. Lovén’s description of the animal of Trichotropis bo- 
realis, it should be referred to this suborder, and equally so by Messrs. 
Forbes and Hanley’s figures, t. II. f. 1; but in examining the animal 
of Trichotropis bicarinatus, the original type of the genus, I find 
that it has a rostrum and no proboscis. I should have been inclined 
to have regarded the animals of these two species as probably form- 
ing-two genera, but Messrs. Forbes and Hanley’s description of the 
animal (Brit. Moll. 361) agrees pretty well with the animal of 7’. bi- 
carinatus. 
F. Ctenoglossa. Teeth on lingual membrane in many series, nu- 
merous, similar (fig. 12). 
Fam. 15, Casstprpa. Mantle enclosed, with a recurved siphon ; 
shell ventricose, subglobose, with a recurved canal, often variced, 
outer lip thickened ; lingual membrane short, broad, triangular, with 
many rows of similar lancet-shaped teeth, and a single small dentated 
tooth in the central series ; operculum annular ; nucleus in the middle 
* In Ann. and Mag. Nat. Hist. x. 415, 1852, by a slip of the pen, I erroneous! 
stated that this animal had no proboscis, “it aa ay 
