MESODESMA. 



Plate II. 



Species 8. (Mus. Cuming.) 



Mesodesma arctata. Mes. testa subtrigono-ovatd, obli- 

 que curvatd, convexo-compressd, valde hKeqidlaterali, 

 latere antico brevissimo, subtruiicato ; ojMco-albd, vix 

 striata, epldermide pallide lutescente indiitd. 



The straitened Mesodesma. Shell somewhat trian- 

 gularly ovate, obliquely curved, convesly compressed, 

 very inequilateral, anterior side very short, subtrun- 

 cated ; opake-white, scarcely striated, covered with a 

 pale yellowish epidermis. 



Gould, Invertebrata of Massachusetts, p. 57. f. 39. 

 Mactra arctata, Conrad. 

 Mactra deaurata, Conrad. 

 Mactra subtriauijuluia. Wood. 



Kab. Cajje Cod, Massachusetts, United States ; Gould. 

 Of a peculiarly obliquely curved growth, very simply 



characterized in other respects. 



Species 9. (Mus. Cuming.) 



Mesodesma cuneata. Mes. testa trigom, subveutri- 

 cosd, iiKCcpiilateraVi, latere postico hreviore, rolundato, 

 antico longiore, laliusculo, decUvi-anyidato ; alba, 

 tenid-striatd, epldermide vix nulla. 



The wedge-like Mesodesma. Shell triangular, some- 

 what ventricose, inequilateral, posterior side the shorter, 

 rounded, anterior longer, rather broad, slantingly an- 

 gular ; white, finely striated, with scarcely any epi- 

 dermis. 



Deshayes, Anim. sans vert. vol. vi. p. 133. 

 Crassatella cuneata, Lamarck. 



Hah. New Zealand ; Hart. 



Chiefly distinguished by the anterior side being the 

 larger and longer. 



Species 10. (Mus. Cuming.) 



Mesodesm.4. striata. Mes. testa subtrhjond, crass'ms- 

 cidd, siibaquilaterali, latere antico subangulato, pjostico 

 rotimdato ; alba, siibruc/ose lirato-striatA et sulcata, 

 epiderndde vix uidlS. 



The striated Mesodesma. Shell somewhat triangular, 

 rather thick, nearly equilateral, anterior side slightly 

 angled, posterior rounded; white, rather roughly ridge- 

 like striated and grooved, scarcely any epidermis. 



Deshayes, Eucyclopedie Methodique, vers, vol. ii. p. 443. 



Julv, 



Mactra striata, Gmelin. 

 Crassatella striata, Lamarck. 

 Erycina striata, Sowerby. 



Hab. 



The most coarsely ridge-like striated of the species. 



Species 11. (Mus. Cuming.) 



Mesodesma donacia. Mes. testa trigono-elongatd, valde 

 compressd, valde inaquilaterali, latere antico breeis- 

 simo, abrupte truncato, postico producto, compresso-at- 

 teuuato ; albidd, concentrlce irregulariter striata, striis 

 paucis minutis radiantibus, epidermide lutescente corned 

 nitente indutd. 



The wedge Mesodesma. Shell triangularly elongate, 

 very compressed, very inequilateral, anterior side 

 very short, abruptly truncated, posterior produced, 

 compressly attenuated ; whitish, concentrically irre- 

 gularly striated, with a few minute radiating strise, 

 covered with a shining yeUowish-horuy epidermis. 



Deshayes, Anim. sans vert. vol. vi. p. 133. 

 Mactra donacia, Lamarck. 



Hab. Chili ; Cuming. 



A fine compressed Z)oH«.i'-shaped species, covered with 

 a beautiful shining horny epidermis. 



Species 13. (Mus. Cuming.) 



Mesodesma ery'cin^ea. Mes. testa snbtrigono-ovatd, 

 latiusculd, compressd, subaquUaterali, latere antico 

 breviore, paululmn truncato, ambobiis rotundatis ,- 

 opaco-albd, leviter striata, epidermide olivaceo-casta- 

 ned indutd. 



The erycina Mesodesma. Shell somewhat triangularly 

 ovate, rather broad, compressed, nearly equilateral, 

 anterior side shorter, a little truncated, both sides 

 rounded ; opake-white, slightly striated, covered with 

 an olive-chestnut epidermis. 



Deshayes, Anim. sans vert. vol. vi. p. 134. 

 Crassatella erycinma, Lamarck. 

 Mesodesma Biemenensis, Quoy. 



Hab. Singapore. 



A compressed ovate shell, with the sides nearly equal, 

 of an opake-white substance, covered with a rich ohve- 

 chestuut epidermis. 



1854. 



