ol 
8. ADACNA. 
1. A. leviuscula (fig. 14). 
Fig. 14.—Adaena leviuscula. 
J, foot. s, siphons. 
§§§ Stphons very large, united at the base ; upper part free, ringed. 
9. Macua. 
1. M. strigillatus, t. 342. f. 5. 
2. M. candidus, t. 344. f. 1. 
10. Azor. 
1. A. coarctatus, t. 344. f. 4. 
§§§§ Siphons elongate, cylindrical. 
11. TAGELUs. 
1. T. viridi-zneus ?, t. 342. f. 1. 
Suborder Il. HerERoconcHz. 
Body not symmetrical. Valves unequal. Cartilage internal, in 
a pit. Hinge simple. Pedal opening inferior. Living lying on 
the side m sand or mud. 
Fam. 6. Myade. 
Siphons elongate, united, covered with a horny periostraca. Gills 
two on each side, dependent. Lips small. Shell porcellanous. 
Hinge toothless. Cartilage-pit in a hollow in one, and a concavity 
in the umbonal surface of the other valve. 
1. Mya. 
1. M. truncata, t. 348. f. 2, 5 (fig. 15). 
Fig. 15.—Mya truncata. 
