MESODESMA.— Plate II. 



Species 13. (Mus. Cuming.) 



Mesodesma heterodon. Mi's. testa oblongo-ovatd, mb- 

 trigond, inaguilaterali, latere antico coticavo - miffit- 

 lato et truncato, crasdiisculo, postico compresso-rotun- 

 dato ; alba, Icevigatd, nitente, epidermide tenui corned 

 lutescente-fuscd indutd. 



The irregulae-toothed Mesodesma. Shell oblong- 

 ovate, subtriangular, inequilateral, anterior side con- 

 cavely angled and truncated, rather thick, posterior 

 compressly rounded ; white, smooth, shining, covered 

 with a thin yellowish brown-horny epidermis. 



Deshayes, MS. (Mus. Cuming.) 



Hab. North-west Australia ; Dring. 



A smooth shining species, covered with a yellowish- 

 brown epidermis, concavely truncated at the posterior end. 



Species 14. (Mus. Cuming.) 



Mesodesma Jauresii. Mes. testa subqnadrato-oblongd, 

 gibbosiusculd, crassd, iutequilaterali, latere antico ob- 

 tuse curvato et truncato, postico swbattenuato-rofun- 

 dato ; opaco-alhd, rugosissime striata, epidermide tn- 

 teo-oUvaced versus marginem, indutd. 



Jaures' Mesodesma. Shell somewhat squarely oblong, 

 rather gibbous, thick, inequilateral, anterior side ob- 

 tusely curved and truncated, posterior siibattenuately 

 rounded ; opake-white, very roughly striated, covered 

 towards the margin with a yellowish-olive epidermis. 



De Joannis, Guerin's Mag. de Zool. 1834. 



Hab. St. George's Bank, Massachusetts, United States ; 

 Gould. 



Particularly characterized by its coarse opake-white 

 roughly striated exterior. 



