DENTALIADtE. 121 



II. AcM^A differs in some anatomical points from Patella, 



and comprises 

 A. testMclinaria, the Tortoise-shell Limpet. 

 A. virginea, a. small shelly with pink rays. 



III. PiLiDiUM fidvum has no eyes on his tentacula, and no 

 fringe on his mantle ; his body is white, and his shell 

 is small, orange-tinted, and slightly curved. 



IV. Propilidium Ancyloides differs from Pilidium chiefly 

 in having the apex of the shell bent backwards instead 

 of forwards, so as to resemble Emargimda without the 

 slit ; it is a very little, conical, white shell, and the 

 animal is as bHnd as his above-named brother. 



DENTALIAD^. 



Of the '' tooth shell '* we have but one authentic example, 

 namely, the 



Dentalium Tarentinum, or entails. — This well-known 

 shell is a long curved tube, tapering at one end, and open 

 at both. The animal lives buried in sand or mud, under water, 

 and feeds upon Foraminifera, and even small bivalves ; it has 

 not a very distinct head ; the foot is conical and pointed, 

 and the breathing apparatus consists of a feather-like appa- 

 ratus of great beauty. 



