OZ TRACHELIPODA. NASSA. 
Chalk, Sussex. It is, however, doubtful whether this is a 
true Eburna. 
Genus X1V.— BUCCINUM. — Linneus. 
Generic Character. — Shell subovate, or ovate-conical, 
seldom elongated, subturreted ; apex a little obtuse; spire 
of medium length, somewhat abruptly acuminate, but sel- 
dom of greater length than the aperture, which is sub- 
orbicular, or a little longer than wide, notched at the base, 
and hardly acute at its upper termination, where there is 
sometimes a small tooth-like process, formed by the thick- 
ening of the inside of the outer lip, with frequently a simi- 
lar tooth opposed to it at the superior part of the inner lip, 
these enclosing a small sinus ; outer lip rather acute at the 
edge, sometimes internally and transversely grooved, and 
in some instances with a dentated margin; columella 
smooth, frequently a little roughened at its inferior extre- 
mity ; canal generally very short and straight ; operculum 
horny and thickened. 
Buccinum prismaticum. Plate III. fig. 34. 
The Buccina inhabit the African coasts, the British seas, and Northern 
Ocean. But few species have been found in a fossil state, and are chiefly niet 
with in the Norfolk, Suffolk, and Essex Crag, some few occur in the London 
Clay and upper marine formations. 
Although Lamarck has done much in distributing many of the Linnzan 
Buccina among other genera, still it would require considerable revision ; 
many, with a lengthened canal, approach too nearly to Fusus, and those 
with a very short canal are nearly allied to Purpura, while others are so 
nearly connected with Terebra, that there is considerable difficulty in distin- 
guishing them. 
The Buccinum undatum, a common shell in the British seas, is the best 
type of the genus. 
Genus XV.—NASSA. — Lamarck. 
Generic Character.—Shell oblong, usually sub-turreted ; 
spire generally of mediocre length, with an acute apex, or 
short, with an obtuse apex ; aperture sub-orbicular, longer 
than broad, notched at the base; outer lip more or less 
thickened, sometimes provided with a small marginal ap- 
pendage close to the upper part, and generally grooved or 
toothed internally ; inner lip much thickened, and, for the 
most part, spread over the lower region of the body in 
front, seldom extending to the base of the shell, and fre- 
quently provided with a small tooth at the superior part 
immediately within the aperture ; columella spiral, its lower 
margin acute, and sometimes ending in a strong point, not 
