208 NEW-YORK FAUNA — MOLLUSCA. 
FAMILY CHAMID. 
Anmau with the mantle opened beneath, merely for the passage of the foot; the edges adherent and minutely 
fringed, united behind by a transverse band, pierced by two orifices, one for breathing and the other for 
the excretions. Marine or fresh water. Suxwt often attached: lateral teeth on the posterior side only ; 
cardinal teeth variable. 
Genus Cuama, Linn. Shell irregular, attached by the lower valve; a single lengthened tooth in one 
valve, and a corresponding groove in the other. 
C. arcinella. (Lam. Vol. 3, p. 683.) Shell subcordate, with the ribs armed with very long spines; 
the spaces between punctated : posterior area large, heart-shaped and verrucose; margin crenulated. 
Color, white, occasionally tinged with rose-red; within, yellowish. Length, 1°5; width, 1-8. 
Florida. 
SECTION 3. CONCHIFERA. 
ANIMAL with the mantle closed: one opening beneath and in front, for the passage of the 
foot, and in the rear exhibiting two extensible, more or less elongated tubes, united or 
distinct ; one beneath for respiration, and the other above for the excrementitious 
dejections. SuEx. subcordiform, equivalve, with radiated sides: hinge of four teeth in 
each valve ; ligament very short. 
FAMILY TELLINIDA. 
Not more than two cardinal teeth on the same valve. Nymphe in general externally promi- 
nent, and covered by a ligament. 
GENUS TELLINA. Lamarck. 
Mantle bordered with tentacular appendages. Gills unequal on each side. Foot much 
compressed, trenchant, and pointed in front. Tubes much elongated, distinct, and entering 
into a fold of the mantle. Shell transverse, subequivalve, compressed, angular and 
somewhat rostrated at the posterior end, where there is an irregular wave-like fold: two 
small cardinal teeth, and generally two lateral teeth in each valve. 
