46 TRACHELIPODA. LITTORINA. 
Genus XLII.— PHASIANELLA. — Lamarck. 
Generic Character, — Shell oblong, smooth ; spire regu- 
Jar, somewhat acuminated ; volutions rather ventricose, 
but the suture not well defined; aperture oblong, entire, 
contracted and acutely angulated at the upper part, and 
rounded at its base ; outer Jip not continuous with the pillar 
lip above ; inner lip white and thickened, especially at the 
base of the columella ; operculum testaceous, thick, spiral, 
externally convex, with its spire on the inner side, to which 
the foot of the animal is adherent. 
Phasianella rigidus. Plate 1V. fig. 26. P. turbinoides. 
Plate V. fig. 15. Both from the Calcaire-grossiér of 
Paris. 
This genus is nearly related to Bulinus in form, but the latter are all land 
shells, whereas the Phasianelle inhabit the ocean. 
Small fossil species of PhasianeJle are found in the London Clay, and in 
the Calcaire-grossier of Paris. 
Genus XLIV.— PYRAMIS. — Brown. 
Generic Character. — Shell generally subulate, gradually 
tapering to a point; body usually short ; spire long ; volu- 
tions but slightly divided by the sutural line, and seldom 
much inflated ; aperture mostly oblong-ovate, placed nearly 
perpendicular, with its upper angle contracted for the most 
part; outer lip not continuous. 
Pyramis nitidus. Plate V. fig. 28. 
The shells of this genus inhabit the ocean, many of the species are found in 
the British Seas, They are rare in a fossil state, and are met with only in the 
newer formations. 
Genus XLV.— LITTORINA. — Ferussac. 
Generic Character. — Shell turbinated, generally ovate, 
or oblong-ovate, for the most part thick and solid; spire 
usually acuminated and subturreted, in some species 
very short, and obtuse at the apex ; aperture entire round, 
or slightly elliptical, sometimes a little acute above; outer 
lip sharp-edged, thickened within ; columella somewhat 
flattened; operculum horny, spiral, consisting of a few 
rapidly enlarging volutions, and furnished with a central 
nucleus, 
Inttorina rudis. Plate V. fig. 8. Found in the Crag at 
Aldborough. 
_ The Littorine have been scattered among the genera Turbo, Phasianella, 
