TRICHOTROPIDA. 293 
Distr.—2 sp. Red Sea, Atlantic, Mazatlan. &. Rollandiana, 
Petit (Ixvii, 50). 
Shell paludiniform, thin, with a brown epidermis; whorls 
ventricose ; aperture ovate-oblique, slightly effused at the base, 
margins disunited; inner lip oblique, rather sinuated in the 
middle; outer lip acute, entire. No operculum. 
Animal pelagic, resembling Ianthina, and like it provided with 
a vesicular float. 
Scaxires, Conrad. 
Distr.—Silurian ; United States. S. angulatus, Conr. (1xvii,51). 
Shell turriculated, whorls flattened above, angulated at the 
shoulder, and convex below; outer lip sinuous; umbilicus none, 
or very small. 
RAPHISTOMA, Hall. Shell turbinated, depressed, flattened and 
angulated above, convex below ; aperture subtrigonal, columellar 
lip excavated in the middle and produced to the right below. S. 
staminea, Hall (Ixvii, 52). 
HOLOPEA, Hall. (Cyclora, Hall.) Isa paleozoic group com- 
posed of incongruous elements. Its first species has been 
referred to Littorinide, another evidently belongs to Naticide, 
a third resembles Ianthina. The species are mostly casts. 
There appears to be no good reason for retaining the group. 
Famity TRICHOTROPID A. 
Shell thin, turbinated, carinated, the ridges with epidermal 
fringes, in fresh or living specimens; columella obliquely trun- 
cated. Operculum lamellar, nucleus external. 
Animal with a short, broad head; tentacles distant, with eyes 
on the middle; proboscis long, retractile. Dentition, central 
teeth single, hamate, denticulated ; uncini three on each side, of 
which the inner is denticulate, the others simple. 
TRIcHOTROPIS, Brod. 
Etym.— Thria« (trichos), hair, and tropis, keel. 
Syn.—Verena, Gray. Tropiphora, Lovén. Ariadna, Fischer. 
Trichophore, Desh. 
Distr.—15 sp. Cireumboreal. 7. borealis, Gould (Ixvii, 53). 
Fossil. Cret.—. 
Characters those of the family. 
IPHINOE, H. and A. Adams. Shell widely umbilicate, aperture 
subtriangular. J. wnicarinatus, Sowb. ([xvii, 54). 
ALORA, H. Adams. Shell ovate-fusiform, slightly umbilicated, 
thin; spire elevated; whorls convex, cancellated with elevated 
spiral ribs and thin lamelle; aperture oval, slightly produced 
in front; inner lip smooth, rounded, slightly reflexed at the fore- 
part; outer lip simple, acute. 7. Gouldii, A. Ad. W. Coast 
Central Am. 
