MACTRA.— Plate XIX. 



Species 107. (Mus. Cuming.) 



Mactra dolabeata. Mact. testa oblongd, trigono-mbqua- 

 dratd, poatice paululum Jdante, aquilaterali, sub letite 

 temnssime transversim striata, nitente-albd, latere an- 

 tioo rotundato-producto, postico abritpte decVwi, obtuse 

 a7igulato ; umbonibiis peculiariter compressis, approxi- 

 matis ; hmnld aredqiie subangnstis, excavatis, lavibus. 



The axe-shaped Mactra. Shell oblong, triangular, 

 subquadrate, posteriorly a tittle gaping, equilateral, 

 beneath the lens very finely transversely striated, 

 shining white, interior side rotundately produced, 

 posterior abruptly slanting, obtusely angled ; iimboes 

 pecidiarly compressed, close ; Innule and area rather 

 narrow, excavated, smooth. 



Deshayes, Pro. Zool. Soc. 1854. 



Hab. ? 



Peculiar in form, the anterior side being produced and 

 rounded, while the posterior is abruptly slanting and 

 angled. 



Species 108. (Mus. Cuming.) 



Mactra silicula. Mact. testa travsversim ovafd, ntrin- 

 qtie paululum Mante, subcequilaterali, transversim 

 tenuistriatd, nitente-albd, marginem versus epidermide 

 stramined sericed indutd, ad angulum posticum sordidd, 

 extremitatibus rotundatis ; lunula aredqne angustis, 

 subexcavatis ; umbonlhis parvls, compressis. 



The little hdsk Mactra. Shell transversely ovate, 

 a little gaping at each end, nearly equilateral, trans- 

 versely finely striated, shining white, covered towards 

 the margm with a silken straw-coloured epidermis, 

 darker on the posterior angle, extremities rounded ; 

 lunule and area narrow, rather excavated ; umboes 

 small, compressed. 



Deshayes, Pro. Zool. Soc. 185-1. 



Hab. Mouth of the Gambia, West Africa (in the sands). 



A transversely oval thin shining white shell, covered to- 

 wards the margin with a straw-coloured epidermis, which 

 on the posterior angle and area is wrinkled up into a darker 

 colour. 



Species 109. (Mus. Cuming.) 



Mactra cuneata. Mact. testa trigono-ovutd, subobliqud, 

 inaquilateraU, lavigatd, sem,ipellucidd, nndique pur- 

 purea aut cinereo-violaced, latere antico rotundato, 

 postico subaugulato-producto ; luuuld aredque distinc- 

 tis, eleganter pUcato-striatls ; umbonibus prominuUs. 



The wedge-shaped Mactra. Shell triangularly ovate, , 

 rather oblique, inequilateral, smooth, semi-pellucid, ! 

 everywhere purple or ash, violet, anterior side rounded, ' 

 posterior rather angularly produced ; lunule and area 

 distinct, elegantly plicately striated ; umboes rather 

 prominent. 



Chemnitz, Conch. Cab. vol. 6. p. 231. pi. 22. f. 215. i 



Mactra purpurea, Spengler. I 



Hab. Nicobar. 



! 

 A semitrausparent glassy purple shell, smooth except on I 



the area and lunule, which are elegantly striated. 



Species 110. (Mus. Cuming.) 



Mactra hepatica. Mact. testd transversim ovatd, gibbo- 

 sissimd, subcequilaterali, lavigatd, poUtd, adlatera sul- 

 cato-striatd, pnrpiweo-lividd, latere antico rotundato, 

 postico subattenuato, lunula aredque subindistinctis, 

 latis, striatis ; umbonibus valde tmnidis. 



The liver-coloured Mactra. Shell transversely ovate, 

 very gibbous, nearly equilateral, smooth, polished, 

 gTOOved-striated at the sides, piu-ple-livid, anterior 

 side rounded, posterior slightly attenuated; lunule 

 and area rather indistinct, broad, striated; umboes 

 much swollen. 



Deshayes, Pro. Zool. Soc. 1854. 



Hab. Island of Negros, Philippines ; Cuming. 



Chiefly distinguished by its swollen gibbous umboes, 

 which gives the shell an ^^;rffl-like aspect. 



Species 111. (Mus. Cuming.) 



Mactra apicina. Mact. testd trigono-ovatd, versus mar- 

 ginem compressd, eequilaterali, transversim sulcato- 

 liratd, versus wnbones lavigatd, albd, nitente, lateri- 

 bus subaqualiter rotundatis; lunuld aredque magnis, 

 eleganter plicato-striatis; umbonibus parvis,eentralibus, 

 oppositis, violaceo tinctis. 



The tipped Mactra. Shell triangularly ovate, com- 

 pressed towards the margin, equilateral, transversely 

 groove-ridged, smooth towards the umboes, white, 

 shining, sides nearly equally rounded ; lunule and area 

 large, elegantly plicately striated; umboes small, 

 central, opposite, tipped with violet. 



Deshayes, Pro. Zool. Soc. 1854. 



Hab. ? 



An equilateral wedge-shaped species, polished white, 

 with the umboes tipped with violet. 



