16 
ft Hinder cardinal teeth smooth. 
2. Venus. 
1. V. verrucosa, t. 314. f. 1, t. 316. f. 2?, t. 316a. f. ]. 
2. V. , t. 316a. f. 5. 
3. V. , t. 316a. f. 4. 
3. Circe. 
1. ? C. minima, t. 317. f. 2. 
b. Anterior lateral teeth none. Cardinal teeth triangular, 
ovate. 
4. Chione. 
1. C. Chione, t. 315. f. 1. 
2. C. florida, t. 316 a. f. 1. 
3. C. beta, t. 316 a. f. 3. 
4. C. gallina, t. 316. f. 3, 7. 
5. C. , t. 316 a. f. 6. 
6. C. fasciata, t. 316. f. 1. 
7. C. opaca, t. 317. f. 4. 
8. C. Thaca, t. 316. f. 5. 
9. C. ovata, t. 316. f. 3. 
Shell 
5. Lucinopsis. 
1. L. undata, t. 317. f. 2. 
c. Anterior lateral teeth none. Cardinal teeth compressed. Shell 
oblong. Hinder lateral tooth none or rudimentary . 
6. Venerupis. Foot byssiferous. 
1. V. perforans, t. 313. f. 4. 
2. V. pullastra, t. 313. f. 7- 
3. V. decussata, t. 314. f. 2. 
4. V. castrensis, t. 315. f. 3. 
5. V. geographica, t. 315. f. 2. 
6. V. Irus, t. 313. f. 5, 6. 
d. Anterior lateral teeth none. Cardinal teeth thick , divergent. 
Shell oblong. Hinder lateral tooth large , strong. 
7 . Trapezium. 
1. T. rostrata (fig. 1). 
Fig. 1 . — Trapezium rostrata. 
f, foot aperture, pp, pedal muscles. 
Fam. 2. Cyprinadee. 
Shell ovate, cordate, covered with a hard dull brown periostraca. 
The hinge-teeth 3 ' 3, triangular ; the front of left valve conical. 
