CONCHIFERA. 
457 
Genus 40. — PSAMMOBIA_ Leach. 
Generic Character. —Transverse, elliptical, or oblong ovate, 
flattened, slightly gaping at one side; beaks prominent; two 
primary teeth in the left valve, and one in the opposite one. 
Psammobia Ferroensis. — The Faroe Psammoma. 
Plate.XC. fig. 12. 
Oblong-oval; white, radiated with crimson; finely striated 
transversely; valves obliquely truncate. One inch and a half 
broad. Inhabits the European seas. 
Genus 41. — SANGUINOLARIA.— Lamarck. 
Generic Character —Transverse, somewhat oval, slightly gap¬ 
ing at the lateral extremities ; upper margin arched, and not 
parallel to the inferior one; hinge with two approximate teeth 
in each valve. 
Sanguinolaria rosea — The Roseate Sanguinolaria. 
Plate XC. fig. 15. 
Semi-orbicular, smooth, shining, and convex; of a beautiful 
rose-colour towards the umbones, which becomes gradually paler 
as it descends; with acute transverse strite. One inch and a 
half broad. Inhabits the sea at Jamaica. 
TRIBE II.-LITHOPHAGI. 
Shells which bore into clay and other substances, with acces¬ 
sory plates, and more or less gaping at their anterior side; liga¬ 
ment external. 
Genus 42. —VENERUPIS.— Lamarck. 
Generic Character. —Transverse, inequilateral; posterior side 
short, the anterior one slightly gaping; hinge with two primary 
teeth in the right valve, and three in the left one, and sometimes 
with three in each; teeth small, approximated, parallel, and 
slightly divergent; ligament external. 
Venerupis perforans — The Perforating Venf.rupis. 
Plate XC. fig. 16. 
Sub-rhombic, transversely striated, wrinkled on the anterior 
side; brown, with a white inside, sometimes with a tinge of 
2 p 
