TRIBE NYMPHACEA. 55 
with concentric ridges, the interstices transversely striated, and in 
parts sub-decussated.1 2. 
V. Disrans. Lam. 5. Rhombie ovate, white, spotted with 
fulvous, finely striated longitudinally, a few distant tranverse ridges. 
—South Seas, Island of St. Peter and St. Francis.—This and the 
preceding closely resemble V. Irus. 
V. Crenata. Lam, 6.—Del. t. 5. f. 2.  Ovate, anteriorly 
rounded, fulvous white, with longitudinal and distant transverse 
grooves, which towards the margin are crenated and ridge-like ; 
violet within. 13.—New Holland. 
V. Carpirorpes. Lam. 7.—Del.t. 5. f. 3. Ovate-oblong 
and obtuse at the extremities, anteriorly narrower, whitish ; girt 
with transverse ridges, the interstices longitudinally ribbed : within 
quite white. 12.—New Holland. Much resembling the last. 
V. Lasonxatrir. Pay. t. 10. f. 11, 12.—Desh. in Lam. 6. 
p-. 164. Orbicular, sub-equilateral, gibbous, transversely grooved 
and longitudinally striated; beaks tumid, hooked and close: 
posterior depression somewhat heart-shaped.— Corsica and Sicily. 
V. Monstrosa. Gray. Ann. Phil. 25.—Venus M. Gimel. 
3280.—D. p. 208.—Ch. f. 445, 6.—W. t. 8. f. 112. Oval, one 
valve larger than the other, dirty white internally, spotted with 
purple, decussated by the striee, rounded at both ends, but broader 
posteriorly. 3..11.—Nicobar Isles. 

TRIBE NYMPHACEA. 
Never having more than two primary teeth in the same valve ; 
often gaping at the lateral extremities: ligament external ; 
nymphe usually projecting outward. 
SecTion.—N. SoLENARIA. 
SANGUINOLARIA. 
Transverse, somewhat oval, slightly gaping at the lateral extre- 
mities ; ventral margin arched, and not parallel to the dorsal 
one; hinge with two approximate teeth in each valve. 
S. Occipens. Zam. 1.—Souen Occipens. Lin. 3228.— 
D. p. 68.—E. t. 226. f. 2.—Ch. f. 61.—W. t. 3. f. 29. Nearly 
elliptic, one end rounded, the other very slightly truncated, rather 
1 We have figured the shell usually considered as this species, 
ot vouching however for its identity. 
