276 MALACOZOA. TROPIOPODA. LAMELLIBRANCHIATA. 



Family VIII. — Tellinina. 



Animal orbicular, roundish, or oblong, more or less 

 compressed ; with the mantle open at its anterior and 

 inferior border, for the passage of the foot, and bordered 

 with tentacular appendages, united behind, but with an 

 aperture for the siphons, which are separated and much 

 elongated ; the foot very much compressed, sharp-edged, 

 and pointed ; two distant adductor muscles. 



Shell orbicular, roundish, or oblong, more or less in- 

 equivalve, inequilateral, the posterior end shorter, flexu- 

 ous ; the hinge with one or two small teeth, and generally 

 obsolete lateral teeth ; the ligament dorsal, short, pro- 

 minent ; the muscular impressions widely separated. 



Genus 1. Kellia. 



Shell roundish or oval, convex, equivalve, closed ; the 

 valves thin, concentrically striate. Hinge of the right 

 valve with two approximated, small teeth, and a remote 

 thin anterior lateral tooth ; that of the left valve with a 

 concave tooth, and a remote lateral tooth ; ligament in- 

 ternal • umbones small, rather obtuse ; muscular im- 

 pressions large, distant. 



This genus, instituted by Turtou, is nearly allied to 

 Amphidesma and Cryptodon. 



1. Kellia suhorhiculdris. Suhorhlcular Kellia. 



Shell roundish-elliptical, nearly equilateral, convex; with 

 the valves very thin, fragile, semitransparent, obsoletely striate 

 concentrically ; the umbones small, rather pointed, incurved ; 

 the hinge with two small teeth and a lateral, in one valve, a 

 concave tooth and a remote lateral in the other; the colour 

 white, hyaline-white, or yellowish-white, often opalescent. 

 Length about five-twelfths of an inch, height a fifth less. 



According to Montagu, the animal, which is of a very pale 

 colour, has a long siphon with only one aperture, and about 

 the middle of the shell beneath a slender foot, half the length 

 of the siphon, and by means of which it can adhere to the 

 smoothest surface. " We first discovered it," he says, "in hard 

 limestone at Plymouth, fragments of which were thrown upon 



