36 
Fam. 4. Carditidi e. 
Foot compressed, conical, rather angulated ^behind. Cartilage 
external, marginal. Hinge-teeth diverging, very oblique. Gills 
two on each side, free behind the body. — For genera, see Ann. <^r 
Mag. Nat. Hist. xiv. 1854, 22. 
1. ? Cardita. 
1. C. spurca, t. 326. f. 5, with two siphonal openings ! 
2. C. calyculata, t. 326. f. 3, t. 35 7. f. 1. 
3. C. antiquata, t. 357- f. 3. 
4. C. sulcata, t. 329. f. 3, t. 357. f* 2, 2 a, 4, 4 a. 
2. Venericardia. 
1. V. australe, t. 346. f. 4. 
Fam. 5. Crassatellidee. 
Gills two on each side, dependent, produced, acute, and united 
behind the base of the foot. Lips four, rhombic. Foot short, 
compressed, triangular, with a deep groove below. Mantle lobes 
free ; hinder end bearded. Anal opening separate. Shell porcel- 
lanous. Hinder teeth 2 ' 3, diverging. Cartilage internal, in a 
triangular pit. 
1. Crassatella. 
1. C. pulchra (fig. 19). 
Fig. 19. — Crassatella pulclira. 
pp f , adductor muscles. 
B. Shell free. Periostraca hard, smooth. Fluviatile. 
Fam. 6. Unionidce. 
Foot compressed, subquadrate, angulated behind. Mantle edge 
smooth, generally bearded behind. Gills two on each side, large, 
dependent. Shell pearly within. Hinge variable, toothed or tooth- 
ess. Periostraca hard, polished, olive. 
