476 MANUAL OF THE MOLLUSCA. 
Animal spinning a byssus; foot thick, lanceolate, grooved $ 
mantle plain or finely fringed; freely open in front; siphons 
moderate, separate half-way or throughout, orifices fringed, 
anal cirri simple, branchial ramose; palpi long, triangular. 
Distribution, 78 species. Norway, Britain, Black Sea, Senegal, 
Brazil, India, China, New Zealand. Low water—100 fathoms. 
(Beechy.) 
Fossil, 6 species. Pliocene—. Britain, France, Belgium, 
Italy. 
The animal is eaten on the continental coasts; it buries in 
the sand at low water, or hides in the crevices of rocks, and 
roots of sea-weed. 
VENERUPIS, Lamarck. 
Etymology, Venus, and rupes, a rock. 
Synonym, Gastrana, Schum. 
Haxample, V. exotica, Pl. XX., Fig. 15. 
Shell oblong, a little gaping posteriorly, radiately striated 
and ornamented with concentric lamella; three small teeth in 
each valve; one of them bifid; pallial sinus moderately deep, 
angular. ; 
Animal with the mantle closed in front, pedal opening mode- 
rate; siphons united half-way, and with a simple fringe and 
tubular valve, branchial siphon doubly fringed, mner cirri 
branching; palpi small and pointed. 
Distribution, 19 species. Britain—Crimea; Canaries, India, 
Tasmania, Kamtschatka, Behring’s Straits—Peru. In crevices 
of rocks. 
Fossil, Miocene—. United States, Europe. 
PETRICOLA, Lamarck. 
Etymology, petra, stone, colo, to inhabit. 
Synonyms, Rupellaria, Bellevue; Choristodon, Jonas; Na- 
ranio, Gray. 
Type, P. lithophaga, Pl. XX., Fig. 16. P. pholadiformis, 
ROR Kiet Ag, 
Shell oval or elongated, thin, tumid, anterior side short; 
hinge with 3 teeth in each valve, the external often obsolete ; 
pallial sinus deep. 
Animal with the mantle closed in front, much thickened and 
recurved over the edges of the shell; pedal opening small ; 
foot small, pointed, lanceolate; siphons partially separate, 
orifices fringed, anal with a valve and simple cirri, branchial 
cirri pinnate ; palpi small, triangular. 
