10 
VENERIRUPIS.—Shell transverse, inequilateral; the posterior side very short, the anterior 
gaping slightly. Hinge with two teeth in the right valve, and three in the left; 
sometimes three in each: the teeth are small, approximate, parallel, and but lit- 
tle or not at all diverging. Ligament external. 
Plate V. Fig. 5. (a) V. perforans. (Venus perforans.—Montagu.) 
(b) Inside of ditto. 
NYMPHACEA.— 10 Genera. 
Two cardinal teeth, or more, on the same valve: shell often gaping slightly at the sides. Ligament 
external; nymphe, in general, projecting outside. 
This family is divided into N. Solenaria, and N. Tellinaria. 
NYMPHACEA SOLENARIA. 
SANGUINOLARIA.—Shell transverse, rather elliptical, gaping slightly at the lateral extre- 
mity; the superior margin arched, not parallel to the inferior. Hinge with two ap- 
proximate teeth in each valve. 
Plate V. Fig. 6. (a) S. rosea. (Solen sanguinolentus.—Gmel.) 
(b) Inside of ditto. 
Psammosta.—Shell transverse, eliiptical or oblong oval, rather flat, gaping slightly at 
each side; beaks rather prominent. Hinge with two teeth on the left valve, and 
one entering tooth in the opposite valve. 
Plate V. Fig. 7 (a) P. cerulescens. 
PsammMor#a.—Shell transverse, oval or oblong oval, gaping a little at the sides; one car- 
dinal tooth in each valve, sometimes in one valve only. 
Plate V. Fig. 8. (a) P. variegata. (Solen variegatus.—Wood.) 
(6) Inside of ditto. 
NYMPHACEA TELLINARIA. 
Is subdivided into—I. Shells having one or two lateral teeth. —And II. Those which 
have no lateral teeth. 
I, _ HAVING ONE OR TWO LATERAL TEETH. 
'TRLLINA.—Shell transverse or orbicular, in general rather flat; the anterior side angu- 
lar, with a flexuous and irregular fold on the margin: only one or two cardinal 
teeth in the same valve; two lateral teeth, often remote. 
(a) Shell transversely oblong. 
Plate V. Fig. 9. (a) T. punicea. (Idem.—Gmel.) 
(6) Inside of ditto. 
(b) Shell orbicular, or rounded oval. 
Plate V. Fig. 10. T. crassa. (Idem.— Lister.) 
