40 



EAST COAST MARINE SHELLS 



PI. 11, Fig. 3 



Chesapeake Bay to Florida; West 



Indies 



ORDER ANOMALODESMACEA 



A much specialized order, the mem- 

 bers mostly of a burrowing nature. This 

 habit has shielded them from many vicissi- 

 tudes and as a result the perfecting proc- 

 esses of selection have been retarded. The 

 members have lagged behind those of other 

 orders and thus indicate more clearly the 

 character of the ancient types from which 

 they sprang . 



Family Periplomatldae 



GENUS PERIPLOMA Schumacher 1817 

 (SPOON SHKLLS) 



Shell almost equivalve, gaping 

 slightly; hinge with a low spoon-shaped 

 tooth In each valve to receive the carti- 

 lage, also a small process resting in 

 front of the teeth and usually removed 

 with the animal. 



PERIPLOMA ANGDLIFERA Philippi. Angulated 

 Spoon. Easily separable on account of the 

 very short posterior end. There is a 

 sharp keel ending in a projecting angle on 

 lower border of right valve. Length 21 mm. 



PI. 6, Fig. 7 



Georgia to Florida Keys and Texas 



PERIPLOMA FRAGILIS Totten. Frail Spoon. 

 Shell thin, fragile, whitish and pearly, 

 right valve most convex, surface marked by 

 lines of growth. Length 15 mm., rarely 

 much larger. Depth range 4-29 fathoms. 

 Labrador to New Jersey 



PERIPLOMA INAEQUIVALVIS Schumacher. In- 

 equal Spoon. Shell thin, fragile, twisted, 

 pearly inside; concentric lines numerous 

 and distinct; angular ridge moderately im- 

 pressed; tooth prominent and broad. 



A recent specimen from Sanibel, 

 Florida, measures 16 mm. A fossil from 

 Clewiston, Florida, is 34 mm. in length. 



PI. 18, Fig. 5 



West Florida; Texas?; West Indies 



PERIPLOMA PAPYRATIA Say. Paper Spoon. 



Shell thin and fragile; one valve more con- 

 vex than the other and extending slightly 

 beyond; umbones inconspicuous; angular 

 ridge extending from umbones to posterior 

 margin; outside surface minutely wrinkled; 

 tooth long, narrow, with an accessory 

 process below; color white and pearly. 

 Height IS mm., breadth 17 mm. 



It is quite a variable species and 

 a rare one. 



PI. 26, Fig. 5 



South Carolina to Gulf of Mexico 



PERIPLOMA UNDULATA Verrlll. Wavy Spoon. 

 A small, thin shell obtained in 541-816 

 fathoms. Length 15 mm. 



PI. 4, Fig. 6 



Off New Jersey to North Carolina 



SUBGENDS COCHLODESMA Couthouy 1824 



Shell Inequlvalve, gaping a little 

 at ends, umbones small; spoon-shaped proc- 

 ess in each valve forming hinge, held by 

 an oblique rib. 



COCHLODESMA LEANDM Conrad. Shell thin and 

 brittle, rib bent backward, surface wrin- 

 kled by growth lines, interior dull white. 

 Length 35 mm., height 25 mm. 



The foot of the animal is broad, 

 compressed; siphons long, narrow, separate. 



This species inhabits sandy beach- 

 es of Cape Cod and Nantucket; also reported 

 south of Casco Bay, Maine. It appears to 

 be more plentiful in the south. It has 

 been dredged in 3-16 fathoms. 



PI. 22, Fig. 1 



Gulf of St. Lawrence to North 



Carolina 



Family Thraciidae 



GENDS THRACIA Blainvllle 1824 



Shell inequlvalve, a little gaping 

 at both ends; umbones prominent, one per- 

 forated. 



THRACIA CONRADI Couthouy. Shell thin, 

 smaller extremity truncated or chopped off; 

 exterior pale ashy-white and pearly under- 

 neath; hinge toothless; Interior chalky- 

 white. Length 3-4 inches. 



When found entire, with both valves, 

 the difference in the size of the valves is 



