HARPA. TRACHELIPCDA. 30 
unfrequently rough ; canal very short, reflected, and never 
projecting beyond the base of the body volution, Fur- 
nished with a horny operculum. 
Nassa reticulata, Plate 1V. fig. 41. Found in the 
Tertiary formations in the neighbourhoed of Nice. 
The shells of the genus Nassa differ from those of Cassis in having mostly a 
longer spire, and a shorter aperture, which can hardly be called elongated ; 
with a shorter canal, which is almost invariably attached to the back of the 
body; in the inner lip being less expanded, and in the varices never being 
formed until the shell is mature. 
The Nass are marine shells, and inbabit the seas of almost all climates. 
Most of the numerous species are grooved, granulated, tuberculated, or 
striated on their outside, in some few instances they are polished. 
Fossil species are few, and are met with in the Crag, Greensand, London 
Clay, and its contemporaneous strata, in Italy and France. 
Genus XVI. — DOLIUM. — Lamarck. 
Generic Character. — Shell subovate, extremely ventri- 
cose, approaching to globular ; thin; more or less strongly 
costated transversely, covered by a thin horny epidermis ; 
spire very short, with a semitransparent apex; aperture 
very large, straitened above, and terminating below in a 
short reflected canal; outer lip thin for the most part, in 
some species a little thickened, reflected and crenated at 
the edge. 
Dolium nodosum, Plate IV. fig. 19. Found fossil in 
the Chaik, at Hurstperpoint, Sussex, and is supposed to be 
the only fossil species of this genus. 
The shells of this genus inhabit the ocean, chiefly the tropics. Some of the 
recent species approach nearly in form to the Buccinea, but their canal not 
being reflected, distinguish them from the latter genus. 
Genus XVI. — HARPA. — Lamarck. 
Generic Character, — Shell oval, ventricose ; spire very 
short, with rounded volutions ; body large, covered with 
longitudinal ribs, which are generally pointed above ; 
aperture large, oblong ovate, much expanded, and terminat- 
ing in a notched base, which can hardly be called canali- 
culate ; outer lip thickened, and a little reflected at the 
edge ; inner lip reflected over the columella, united to the 
outer lip above, and terminating in a point below. 
Harpa mutica. Plate V. fig. 25. Found fossil in the 
Calcaire-grossier at Grignon, Bordeaux and Volognes, 
and is the only fossil species known. 
The Harp inhabit the ocean, and are all natives of the Indian seas. They 
are but few in number. 
Cc 
