136 

 GEN. XIII. 



ARCA. 



A?wnal a TETHYS. 

 SHELL; bivalve, equivalve. 



Hinge ; with many teeth, alternately locking between 

 each other. 



1. ^ 



PiLOSA. Area pilofa. Lin. Syft. p. 1143. 182. 



Gmd. Syft. p. 3314. 36. 



Puh. Cai.Dorfct. p. 35. 



Turt. Lin. iv. p. 256.—GuaJt. t. 73. A. 



C/ieni. Conch, vii. t. 57. f. 565. 566. 



Lifter Conch, t. 247. f. 82. 

 Area Glycymeris. Br. Zool. t. 58. f. 58. 



Don. Br. Shells, ii. t. 37. 



Lin. Trans, vi. t. 18. f. 1. 2. (IVooil.) 

 Glycymeris orbicularis. Da Cofta p. 168. t. 11. f. 2. 2. 



A. with a flrong-, orbicular fliell, covered with a dark 

 brown, pilous epidermis, particularly about the margin ; 

 beneath this the older (hells are fometimes of a rufty brown 



colour. 



