558 



In fize it Is equal to L. anaiifera, but differs confide- 

 rably in the formation of its component parts or plates : 

 the upper valves are pointed at the apex, and turn back- 

 wards, giving the front of the fliell a convexity ; where- 

 as the other is rather concave : the dorfal valve fpreads 

 greatly at the bafe, and forms a confiderably fharp, pro- 

 minent angle, whereas in anatifcra, this valve is regu- 

 larlv femi-circular. 



PHOLAS. 



Dactylus, Pholas Da£tylus. Doti. Br. ZooJ. iv. t. 118. 



, i ' " ' This fhell has four acceffory valves ; the one, not be- 



fore defcribed, is very fmall, and ftands ereft at the in- 

 ner end of the two large plates to fupport them. The 

 difficulty of obtaining them quite perfeft, occafionedus 

 to believe it had only three. 



Crispatus. Solen crifpus. Gmd. Syfi. p. 322S. 



Gmelin has miftaken Lister's fliell, which is Pholas 

 crifpatus, and therefore has defcribed this in hoxh. genera. 



Candidcs. Pholas Candida. Don. Br. Shells, iv. t. 13L\ 



p. 2\. 



Pholas 



