MESODESMA. 



Plate III. 



Species 15. (Mus. Cuming.) 



Mesodesma Macteoides. Mes. testa elongato-ohlongd, 

 ad umhones trigond, tenniadd, inaquilaterali, utrinfjue 

 hiante, latere aidico declivi-rotundato, postico pro- 

 ducto ; subpellucido-albd, nitenta, ad latere striata, ad 

 marginem epiderm.lde fumo-nigrd indiitd. 



The Mactra-like Mesodesma. Sliell elongately ob- 

 long, triangular at the umboes, rather thin, inequi- 

 lateral, gaping at both euds, anterior side slantingly 

 rounded, posterior produced ; subtransparent-white, 

 shining, striated at the sides, covered with a brown- 

 black epidermis at the margin. 



Deshayes, MS. (Mus. Cuming.) 



Hab. Australia. 



Of a somewhat distinct typical character, of a thinnish 

 subpellucid texture, elongately oblong in form, rounded 

 and gaping at each cud. 



Species 16. (Mus. Cuming.) 



Mesodesma plana. Mes. testa oblique trigono-orbicu- 

 lari, compresso-plaiid, inaquilaterali, latere antico 

 paululum breviore ; albidd, concentrice striata, epider- 

 mide tenui lutescente-sericed indutd. 



The flat Mesodesma. Shell obliquely triangularly or- 

 bicular, compressly flattened, inequilateral, anterior 

 side a little the shorter ; whitish, concentrically stri- 

 ated, covered with a thin yellowish silky epidermis. 



Hanley, Pro. Zool. Soo. 1843, p. 102. 



Hab. Island of Ticao, Philippines ; Cuming. 



A convexly compressed rather solid species, having very 

 much the appearance of au Astarte. 



Species 17. (Mus. Cuming.) 



Mesodesma intee^iedia. Mes. testa trigono-ovntd, 

 crassiiiscidd, latere antico brevi, angulato-tnmcato, 

 postico rotiindato ; ftiscescente-albd, siibrugoso-striatd, 

 ad umbones leevigatd. 



The inteemedi.ate Mesodesma. Shell triangularly 

 ovate, rather thick, anterior side short, angularly 

 truncated, posterior rounded; fuscous-white, rather 

 roughly striated, smooth at the umboes. 



Deshayes, MS. (Mus. Cuming.) 



Hab. ? 



July, 



Of more solid growth than the preceding species, and 

 of more regular triangular form. 



Species 18. (Mus. Cuming.) 



Mesodesma spissa. Mes. testa trigono-oblongd, crassd, 

 antice subacute angulatd et truncatd, postice rotuu- 

 datd, ad umbones compressd, area posticd latiusculd, 

 subconcavd ; fuscescetde-albd, irregulariter striatd. 



The massive Mesodesma. Shell triangularly oblong, 

 thick, anteriorly rather sharply angled and truncated, 

 posteriorly rounded, compressed at the umboes, pos- 

 terior area rather broad, subconcave ; light fuscous- 

 white, irregularly striated. 



Hab. New Zealand ; Hart. 



A rather large Dowoar-shaped species, of solid growth 

 and of a stone-white semifossil aspect. 



Species 19. (Mus. Cuming.) 



Mesodesma teigona. Mes. testa trigono-ovatd, crassd, 

 gibbosd, snbaqiiilaterali, postice rotmidald, antice sub- 

 angidato-rostratd, area untied lata, siihcordiformi ; 

 albidd, rufescente-fulvo sparsijn tinctd, concentrice ir- 

 regulariter liratd et striatd, versus umbones lavigatd, 

 nitenfe. 



The teiangular Mesodesma. Shell triangularly ovate, 

 thick, gibbous, nearly equilateral, posteriorly rounded, 

 anteriorly rather angularly beaked, anterior area broad, 

 somewhat heart-shaped ; whitish, sparingly tinged 

 with reddish-fulvous, concentrically irregularly ridged 

 and striated, smooth, shining towards the umboes. 



Deshayes, Ency. Mcth. vers. vol. ii. p. 444. 



Hab. ? 



This approaches more than any to the typical form of 

 Cra.ssatella, represented by C. I'ostrata. 



Species 20. (Mus. Cuming.) 



Mesodesma glabrata. Mes. testa trigono-ovatd, com- 

 pressd, solidiusculd, subtequilateraH, postice rotundatd, 

 antice obtuse angulatd, ared antied oblongo-cordatd ; 

 concentric^ corrugato-liratd, ad umbones glabrata. 



The smooth Mesodesma. Shell triangularly ovate, 

 compressed, rather solid, nearly equilateral, poste- 



1854. 



