56 



GLYCIMERIS Vagina. 



TAB. DCXXXVI. 



Spec. Char. Transversely oblong-ovate, com- 

 pressed^ smooth ; the anterior portion much 

 the larger, rather attenuated and slightly con- 

 vex ; the posterior flattened, truncated, more 

 or less angular. Width to the length as 7 to 3. 



Syn. Glycimeris Vagina, Wood in ^nn. and Mag. 

 Nat. Hist. V. 6. 245. Morris, Catal. 88. 



The different degrees of convexity of the two parts of this 

 shell, which give to each valve when separate a peculiar 

 twisted appearance, and the great distance of the umbones 

 from the anterior extremity, will at first sight serve to di- 

 stinguish it from the recent G. Sil/qua, which is the only 

 species at present known that resembles it. The rectan- 

 gular form of the fulcra, and the angular, not rounded, 

 outline, are additional characters. Neither does it appear 

 to have\the umbones eroded, as they generally are in G. 

 Siliqua, and in many shells of the northern seas, as well as 

 in those which live in lakes and freshwater rivers: it pro- 

 bably lived in a temperate climate, or at least in a situation 

 where vegetable substances were not decaying around it. 



From the coralline Crag of Ramsholt, in the cabinets 

 of the Rev. R. Wilson and 8. V. Wood, Esq. ; the latter 

 irentleman has also traced it in the red crag of Sutton. 



