MESODESMA. 



Plate IV. 



Species 22. (Mus. Cumiug.) 



Mesodesma angulhs. Jfe. testa acute oblique oMongo- 

 angulatd, compressd, autice brevissime tnmcatu, ab- 

 rupte return, ad umbones mbrostratd, postice temii-ro- 

 tundatd; nitente-alhd, obsolete lineari-sulcatd. 



The angle Mesodesma. Shell sharply obliquely ob- 

 long-angled, compressed, anteriorly very shortly trun- 

 cated, abruptly blunted, somewhat beaked at the um- 

 boes, posteriorly thinly rounded ; shining white, ob- 

 soletely linearly grooved. 



Deshayes, MS. (Mus. Cuming.) 



Hab. Philippine Islands. 



A small, highly-polished, subtransparent white shell, 

 remarkably abruptly shortened at the posterior end. 



Species 23. (Mus. Cuming.) 



Mesodesma macrodon. Mes. testa siMrigotio-orbiailari, 

 subaquilaterali, lateribus ambobus declivibiis, delude 

 rotundatis, antico paido bremore ; albidd, coiiceidrice 

 sulcata et Virata, Uris versus nmboiies obsoletis. 



The LARGE-i'ooTHED Mesodesma. Shell somewhat tri- 

 angularly orbicular, nearly equilateral, both sides 

 slanting, then rounded, anterior side a little the 

 shorter ;t whitish, concentrically grooved and ridged, 

 ridges obsolete towards the umboes. 



Deshayes, MS. (Mus. Cuming.) 



Hab. ? 



A small, Astarte-shs^td. species, strongly but somewhat 

 irregularly ridged towards the margin. 



Species 24. (Mus. Cuming.) 



Mesodesma retosa. Mes. testa subquadrato-oblongd, 

 tenniculd, concavd, valde inaquilaterali, latere antico 

 pecuUariter brevi et truncato, postico rotundato ; al- 

 bidd, obliqiii concentrice striata, ad umbones cameo 

 tinctd, versm mai-giuem epidermide luteo-fuscd indutd. 



The blunt Mesodesma. Shell somewhat squarely ob- 

 long, rather thin, concave, very inequilateral, anterior 

 side peculiarly short and truncated, posterior rounded ; 

 whitish, obliquely concentrically striated, tinged with 

 flesh at the umboes, covered towards the margin with 

 a yellowish-brown epidermis. 



July, 



Deshayes, MS. (Mus. Cuming.) 

 Hab. ? 



A rather thin obliquely oblong species, peculiarly ab- 

 ruptly sliortened on the posterior side, having somewhat 

 the typical form of Cypricardia. 



Species 25. (Mus. Cuming.) 



Mesodesma lanceolata. Mes. testa trigono-lanceolatd, 

 cuneiformi, valde inaquilaterali, latere antico twmidi- 

 Ksculo, abrvpte truncato, lalo, postico lanceolato-attenu- 

 ato ; albidd, nitente, paruiii striata. 



The lanceolate Mesodesma. Shell triangularly lan- 

 ceolate, wedge-shaped, very inequilateral, anterior side 

 rather swollen, abruptly truncated, broad, posterior 

 side lanceolately attenuated; whitish, shining, but 

 little striated. 



Deshayes, MS. (Mus. Cuming.) 



Hab. North-west Australia ; Drinsr. 



The most peculiarly elongated wedge form of the genus. 



Species 26. (Mus. Cuming.) 



Mesodesma crassula. Mes. testa oblique trigono-orbi- 

 cnlari, subpland, lateribus ambobus declivibus, deinde 

 rotundatis, antico breviore ; albidd, ad umbones obscure 

 radiatd, leviter striata, versus marginem epidermide 

 teuui corned nitente indutd. 



The tiiickish Mesodesma. Shell obliquely triangu- 

 larly orbicular, rather flat, both sides slanting, then 

 rounded, anterior the shorter; whitish, obscurely 

 rayed at the umboes, faintly striated, covered towards 

 the margin with a thin shining homy epidermis. 



Deshayes, MS. (Mus. Cuming.) 



Hab. ? 



Closely allied to M. plana, but of less solid texture. 



Species 27. (Mus. Cumiug.) 



Mesodesma sulcata. Mes. testa trigono-ovatd, subveti- 

 tricosd, aqnilaterali, latere antico latiore, concentrice 

 sulcata et dense liratd, Uris ad aream posticam leviter 

 elevatis ; lutescente-albd. 



The grooved Mesodesma. Shell triangularly ovate, 

 rather ventricose, equilateral, anterior side the broader, 

 1854. 



