CO^CUYLW—VITHYRA. 53. 239 



under the ligament on the anterior side, which terminates in a 

 depression. Ligament external. 



Anodon iestii ovatd tumidd infT'quilaierali, margine arcuato, Cyfrueus. 

 latere anlko angustalo avnminato. '' 



Shell oval tumid inajquilateral, arcuated at the margin, with 



the anterior side narrowed to a point. 



MyJilus Cygneus. Linn. Syst. Nat. p. 1158. 



Crmelin, Syst. p. 3355. 



Tiu'ton, Linn. Syst. iv. p. 293. 



Pennant, iv. p. 239, tab. 70. 



J)a Costa, p. 214. tab. 15. fig. 2. 



Chemnitz, viii. p. 185. tab. 86. fig. 762. 



Donovan, British Shells, ii. tab. 55. 



3lontagu, Test. Brit. p. 170. 



Linn. Trans, viii. p, 109. tab 3. A. fig. 2. 



Turton, British Fauna, p. 165. 



Dorset Catal. p. 40, tab. 12. fig. 42. 



Dillwyn, Descript. Catal. p. 315. 



Turton, Conch. Diet. p. 115. 

 Musculus latus. Lister, Conch, tab. 156. fig. IL 

 Mns. nost. Common in rivers, ponds, and canals. 



Shell growing to two or three inches long, and six or seven 

 broad, green or pale brown, wrinkled or striate transversely, pro- 

 duced at tlie anterior side to a ratiier pointed termination, with 

 the margin opposite the hinge curving outwards : beaks minute, 

 with the rejrion about them sometimes decorticated. 



