TELLINA. 143 



Tellens they have formed three new genera, namely, 

 Pandora, Capsa, and Lucina. 



The animals inhabiting this genus differ but very 

 little from those which occupy the shells of the genus 

 Cardium and Venus. They are provided, before, with 

 two simple and very long siphons, one of which (the 

 largest) serves for the passage of the food, and the other 

 for that of the excrements. They have, besides, a lingui- 

 form muscle, which projects from the hind part of the 

 shell, and serves for a foot. These animals form the 

 genus Peroncea of Poli, who has given elaborate ana- 

 tomical figures of them, in his splendid work on the 

 Testacea of the Two Sicilies. What locomotion they 

 possess is effected by opening and shutting the valves, 

 at the same time lengthening and contracting their foot, 

 by which means they accomplish their purpose, and 

 move as far through the mud, or sand, as their limited 

 powers of exertion will permit, or their wants require. 



