54 TESTACEOUS MOLLUSCA. 
white, with radiating ribs, but anteriorly smooth; with scattered 
concentric lamella ; lunule distinct. = ..14.— Peru. 
P. Soutipa. Sow. Z. P. 1834. Sub-globose-elliptic, palish, 
the umbones and the extremities brownish violet, with radiating 
ribs but anteriorly smooth, the lines of growth sometimes sub- 
lamellar and anteriorly more prominent. 1.. 1;3,.— Peru. 
P. Discors. Sow. Z. P. 1834. Oblong-elliptic, brownish, 
with radiating acute riblets, but anteriorly smooth; dorsal edge 
straight. 31..4.—Peru. 
P. Conctnna. Sow. Z. P. 1834. Oblong, pholas-shaped, 
whitish, with concentric riblets; posteriorly rounded, and longitu- 
dinally grooved; back sloping, with a smooth lamella on one of the 
valves : anteriorly rather acuminated, with crowded, concentric, 
ridge-like riblets. <45..4—Mons. Christi. 
P. Bipentrata.* Gray Ann. Phil. 25—Mya B. Mont. t. 
26. f. 5. p.99.—D. p. 45. Sub-oval, compressed, dirty-white: one 
valve with two broad flat distant diverging teeth, which project 
forwards obliquely, the other toothless, and having only a small 
cavity under the hinge. a .i.— England. 
VENERUPIS. 
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. 
V. Perrorans.* Lam. 1.—Vunus P. Mont. t.3.f. 6.—Turt. 
_ B. t. 2. f. 15 to 18.—D. p. 206.—W. ¢t. 8. f. 108. Sub- 
rhomboidal, margins nearly parallel, with concentric strie, forming 
ridges at the sub-truncated anterior end, crossed by fine longitudinal 
ones, white or brownish, with purple zigzag stripes : hinge with two 
of the teeth cloven, syphon mark broad, and adjacent to the marginal 
impression. 1.,21. rarely so large.— England, &c. 
V.Nucuevus. Lam.2.—Del. t. 5. f. 1. Ovate, the extremities 
obtuse, smooth at the umbones, transversely striated ; anterior side 
lamellar: three teeth in one valve and two in the other. $.— 
Rochelle. 
V. Irvs. Lam. 3.—Donax I. Lin. 1128.—D. p. 156.— 
Ch. f. 268, 9.—Don. t. 29. f. 2.—W. t. 6. f. 21. Sub-oval, 
variable in its outline, usually truncate, margin nearly parallel and 
straight, brownish white with elevated, concentric, distant, reflected 
ridges and longitudinal striz in the interstices. }..3.—Mediter- 
ranean. 
V. Exotica. Lam. 4. Oval oblong, and the extremities obtuse, 
