MACTRA. 



Plate XVII. 



Species 86. (Mus. Cuming.) 



Mactka coxtraria. Mact. testii ovato-tri.gond, aqidla- 

 terali, comirresslmculd, nitidd, transveisim obsoleli 

 tenuisdme striatd, utroque latere convexo, declivi, sui- 

 m/f/tdatis, nuirgme inferiore valde arciiato ; lunuld 

 arenque sidca/is, sidcls Imnda profnudis, iiiferiii con- 

 vergentibus^ rugis brevibus ad extremitate anticd, al- 

 bidd ; umboinbus miidmis, violaceo-tinctis. 



The contrary Mactra. Shell ovately triangular, equi- 

 lateral, rather compressed, shining, transversely ob- 

 soletely very finely striated, rather convex, slanting 

 and slightly angled on both sides, lower margin very 

 much arched ; lunule and area grooved, grooves of 

 the lunule deep, converging at the lower part, with 

 short wrinkles at the anteinor extremity, whitish; 

 umboes very small, tipped with violet. 



Deshayes, Pro. Zool. Soc. 1854. 



Hah. ? 



A rather thin triangularly compressed shell, peculiarly 

 plait-wrinkled at the anterior extremity, with the umboes 

 tipped in a characteristic manner with violet. 



Species 87. (Mus. Cuming.) 



SIactra iNjEauALis. Mact. testa ovaio-transversd, sub- 

 trigond, inieqidlaterali, compressmsculu, ad margineni 

 wferiorem acidiuscidd, poUtd, nUente, epidermide Jla- 

 vescenle corned indutd, latere antico lougiore, mhatte- 

 nuato, obtuso, postico angidato ; lunuld aredque tenui- 

 pltcafis ; umbonibus brevibus, acutis, oppositis. 



The unequal Mactra. Shell ovately transverse, sub- 

 triangular, inequilateral, rather compressed, rather 

 sharp at the lower margin, polished, shining, covered 

 with a yellowish-horny epidermis, anterior side the 

 longer, rather attenuated, and obtuse, posterior an- 

 gled ; lunule and area thinly plicated ; umboes short, 

 sharp, opposite. 



Deshayes, Pro. Zool. Soc. 185-t. 



Hab. China Sea. 



A smooth pallid shell, covered towards the margin with 

 a warm yellowish-horny epidermis, peculiar in having the 

 anterior side longer than the posterior. 



Species 88. (Mus. Cuming.) 

 Mactra transversa. Mact. testa ovato-oblongd, irans- 



May, 



vei'sd, subceqidlaterali, soUdiusculd, compressd, albidd, 

 epidermide squalide Jtavicaide, trausversim regulariter 

 suleatd, latere antico declivi, subacuminato, postico au- 

 gulo acido inferne lerminato, oblique truncato, miguhi 

 decurrente ; umbonibus parvis, acutis, op/jositis. 



The transverse Mactra. Shell ovately oblong, trans- 

 verse, nearly equilateral, rather solid, compressed, 

 whitish, covered with a dull yellowish epidermis, re- 

 gularly transversely grooved, anterior side slanting, 

 rather acuminated, posterior terminating at the lower 

 part with a sharp angle, obliquely truncated, with an 

 angle miming down ; umboes small, sharp, opposite. 



Deshayes, Pro. Zool. Soc. 1854. 



Bab. ? 



A. triangularly compressed shell, of rather solid growth, 

 transversely grooved, covered with a dull ochraeeous epi- 

 dermis. 



Species 89. (Mus. Cuming.) 



Mactra elegans. Mact. testa rotundato-trigond, tumidd, 

 tenui, diaphano-albd, epidermide Jibrosd ad marginem 

 indutd, cBquilaterali, antice rotmidatd, postice subros- 

 tratd et lamellato-carinatd, trausversim concentricii nn- 

 dique costatd ; lunuld cordatd, concavd, IrBvigatd, area 

 angustd, concavd, utrinque carhiatd ; imibonibus ap- 

 proximatis. 



The elegant Mactra. Shell rotundately triangular, 

 swollen, thin, diaphanous-white, covered at the mar- 

 gin with a fibrous epidermis, equilateral, anteriorly 

 rounded, posteriorly slightly beaked and lameUately 

 keeled, transversely concentrically ribbed throughout; 

 lunule heai't-shaped, concave, smooth, area narrow, 

 concave, keeled on each side ; umboes close. 



Sowerby, Tankerville Catalogue, Appendix, p. 3. pi. 1. f. 3. 



Hab. Florida. 



This truly elegant species, first described and figured 

 by Mr. Sowerby in the Tankerville Catalogue, is of a 

 triangularly globose form, and of thin diaphanous-white 

 substance, prominently concentrically ribbed throughout. 



Species 90. (Mus. Cuming.) 



Mactra subtruncata. Mact. testa ovato-subtrigond, in- 

 cequilaterali, transversim striato-sulcatd, sub epider- 

 mide sordide Jlavescente o-etaceo-albd, latere antico ro- 



1854. 



