EAST COAST MARINE SHELLS 



43 



POLYMESODA FLORIDANA Conrad. A much thin- 

 ner and smaller shell than the preceding 

 one and not so swollen; surface dull; in- 

 terior touched with purple at margins as 

 in C. carolinensis. Length slightly under 

 1 inch. 



PI. 13, Fig. 4 



Big Pine Key, Florida, northward 



and westward to Texas 



POLYMESODA FLORIDANA SARASOTAENSIS Hender- 

 son. 



PI. 25, Fig. 8 



West Florida 



Family Astartidae 



A family of ancient origin. Liga- 

 ment external; surface of shell often dull 

 but soft parts brilliantly colored, usual- 

 ly yellow orange or vermillion. 



The conditions of life favor many 

 individuals rather than number of species 

 with consequent extreme variation. For 

 this reason many of the species are diffi- 

 cult to identify. 



They live partly covered by mud or 

 sand, mostly in boreal seas, and form a 

 large proportion of the food consumed by 

 walrus and many fish. 



There are a number of deep water 

 species: the following are those which 

 occur in comparatively shallow water and 

 are most likely to be found dead upon the 

 beaches. 



GENUS ASTARTE Sowerby 1816 



ASTARTE CASTANEA Say. Chestnut Astarte. 

 The typical form is smooth, polished, of a 

 rich reddish chestnut brown color. Margins 

 sharply crenulated. Length 23 mm. 



PI. 13, Fig. 10 



PI, 73, Fig. 7 



Nova Scotia to Cape Hatteras, North 



Carolina 



ASTARTE CASTANEA PICEA Gould. Pitch-pine 

 Astarte. This variety possesses a black- 

 ish tarry epidermis. 



Chelsea Beach, Massachusetts to 



New Jersey 



ASTARTE CASTANEA PROCERA Totten. Epidermis 

 dxill yellowish brown. 



Provincetown Harbor, Massachusetts 



ASTARTE QUADRANS Gould. A small qxzadrate 

 species with a glossy shell; anterior end 

 longest; ijmbones not inclined to either 

 side, pointed: surface smooth; small lat- 

 eral tooth on left valve and corresponding 

 groove on right valve. Length 6 mm. 

 Depth range 5-104 mm. It has been found 

 in fish stomachs. 



PI. 22, Fig. 6 



PI. 73, Fig. 4 



Labrador to Chesapeake Bay 



ASTARTE UNDATA Gould. Shell dark brown, 

 variable in outline, ten to twenty-five ccn- 

 centric ripples. Depth range 5-104 fath- 

 oms. 



PI. 73, Fig. 1 



Greenland to Massachusetts Bay and 

 south in colder water to Chesa- 

 peake Bay 



Family Crassatellldae 



Shell solid, slightly inequivalve, 

 inequilateral; posterior end longer; three 

 cardinal teeth in right valve, two in left; 

 only concentric sculpture and that often 

 present only near xombones. 



GENUS CRASSATELLA Lamarck 1801, not 1798 



CRASSATELLA GIBBSII T. and H. (C. floridana 

 Dall) . Concentric grooves about 1 mm. 

 wide, covered with fine bright brown epi- 

 dermis; tip of umbones flattened; interior 

 pinkish chocolate, pink or white; margins 

 smooth in all ages. Length 65 mm. Range 

 3-100 fathoms. Fossil in the Pliocene 

 marl near Clewiston, Florida. 



PI. 10, Fig. 10 



North Carolina to West Indies 



GENUS CRASSINELLA Guppy 1874 



Shell equivalve, often three-sided; 

 lunule distinct; two cardinal teeth in one 

 valve, one cardinal on other yalve; two an- 

 terior marginal teeth on each valve. 



CRASSINELLA MACTRACEA Linsey. Shell small, 

 almost quadrant-shaped; fine concentric 

 waves upon surface and minute radiating 

 lines between them; lunule long and deep; 

 color pale yellowish green. Diam. 6 mm. 



The peculiar shape and striae ra- 

 diating from the umbones separate this 



