CONCHIFERA. 479 
G. cuneatus was formally eaten by the Indians. At Mobile, 
on the Gulf of Mexico, it is found in colonies along with Cyrena 
Carolinensis, burrowing 2 inches deep in banks of mud; the 
water is only brackish, though there is a tide of 3 feet. Banks 
of dead shells, 3 or 4 feet thick, are found 20 miles inland: 
Mobile is built on one of these shell-banks. The road from 
New Orleans to Lake Pont-chartrain (6 miles) is made of 
Gnathodon shells procured from the east end of the lake, where 
there is a mound of them a mile long, 15 feet high, and 20—60 
yards wide; in some places it is 20 feet above the level of the 
lake. (Lyell.) 
LuTRARIA, Lamarck. Otter’s-shell. 
Type, L. oblonga, Gmel. Pl. XXI., Fig. 3. (= L. solenoides, 
Lamarck). 
Shell oblong, gaping at both ends; cartilage-plate prominent, 
with 1 or 2 small teeth in front of it, in each valve; pallial 
sinus deep, horizontal. 
Animal with closed mantle-lobes ; pedal opening moderate ; 
foot rather large, compressed; siphons united, elongated, in- 
vested with epidermis; palpi rather narrow, their margins 
plain; gills tapering to the mouth. 
Distribution, 18 species. United States, Brazil, Britain, Medi- 
terranean, Senegal, Cape, India, New Zealand, Sitka. 
Fossil, 25 species. Carb.—. United States, Hurope. 
Resembles Mya; burying vertically in sand or mud, especially 
of estuaries; low water, 12 fathoms. JL. rugosa, found living 
on the coasts of Portugal and Mogador, is fossil on the coast 
of Sussex. (Dixon.) 
Sub-genus, Vaganella, Gray. Mantle sinus, large, round; 
interior ridges, of which two diverge from the hinge to the 
ventral edge. 
ANATINELLA, G. Sowerby. 
Type, A. candida, (Mya) Chemn. Pl. XXIII., Fig. 6. 
Shell ovate, rounded in front, attenuated and truncated be- 
hind; cartilage in a prominent spoon-shaped process, with 2 
small teeth in front; muscular impressions irregular, the 
anterior elongated; pallial line slightly truncated behind. 
Distribution, 3 species. Ceylon, Philippines; sands at low 
water. 
FAMILY XVI.—TELLINIDA. 
Shell free, compressed, usually closed and equivalve ; cardinal] 
teeth 2 at most, laterals 1—1, sometimes obsolete; muscular 
