MACTRA. 



Plate XV. 



Species 73. (Mus. Brit.) 



Mactra bilineata. Mad. testa oblon/jo-ovatd, mhcom- 

 premd, peUucuIo-albd, epidermide sericed sparsim in- 

 dutd, ii/aqnilaterali, latere antico rotundato, postlco 

 longiore, subobsoleti concavo-anr/ulato , aiigulo utrinqite 

 I'meari-carinato ; lunula vix nulla. 



The bilineated Mactra. Shell oblong-ovate, rather 

 compressed, transparent white, covered here and there 

 with a silky epidermis, inequilateral, anterior side 

 rounded, posterior longer, somewhat obsoletely con- 

 cavely angled, angle linearly keeled down each side ; 

 scarcely any lunule. 



C. B. Adams (Mus. Cuming). 



Hab. Jamaica. 



A clear subtransparent shell, partially covered with a 

 slight silky epidermis, characterized on the posterior side 

 by a bi-liuearly keeled angle. 



Species 73. (Mus. Brit.) 



Mactra Tellinoides. Mact. testd subtrigono-ovatd, 

 opaco-albd, lavigaid, epidermide fiiscesceute sparsim 

 induld, inaqidlaterali, latere antico brevi, rotundato, 

 postico late anijulato et producto ; umbouibus acutis ; 

 lunula vix nulla. 



The Tellen-like Mactra. Shell somewhat triangu- 

 larly ovate, opake-whito, smooth, sparingly covered 

 with a light brown epidermis, inequilateral, anterior 

 side short, rounded, posterior broadly angled and 

 produced; umboes sharp, scarcely any lunule. 



Conrad, Journ. Acad. Nat. Sci. Philadelphia. 



IM, ? 



This species differs from the following in being of an 

 opake chalk-white and smooth, whilst that is shiuing white 

 and strongly striated. 



Species T-l. (Mus. Brit.) 



Mactra sdblanceolata. Mact. testa subtriijono-ovatd, 

 alba, inaqidlateraU, lateribus ambobus subanyulatis, 

 latere antico transversim striata, postico louffiore, sub- 

 lanceolato, tnimcs striato ; lunula indistinctu, area pos- 

 ticali lata, subconcata. 



Tite sublanceolate Mactra. Shell somewhat trian- 



gularly ovate, white, inaequilatcral, both sides rather 

 angular, anterior side transversely striated, posterior 

 longer, sublanceolate, less striated ; lunule indistinct, 

 posterior area broad, rather concave. 



Deshayes, Pro. Zool. Soc. 1854. 



Ilab. ? 



A shining white species, sharply transversely striated, 

 chiefly on the posterior side, with a rather broad wedge- 

 like area on the posterior side. 



Species 75. (Mus. Cuming.) 



Mactra cornea. Mact. testa subtrigond, temii, oentri,- 

 cosd, transversim tenuistriatd, striis irregularibus, ad 

 latera rugosis ; incarnato-albd, obscure concentrice fas- 

 data; subcequilaterali, latere antico rotundato, postico 

 longiore, suhprodudo ; lunula ampld, .%ubliidistinctd ; 

 iimbonibus conspicuis, corifertis. 



The horny Mactra. Shell somewhat triangular, ven- 

 tricose, transversely finely striated, stria; irregular, 

 rugose at the sides ; flesh-white, obscurely concen- 

 trically banded ; nearly equilateral, anterior side 

 rounded, posterior longer, somewhat produced ; lu- 

 nule large, rather indistinct ; umboes conspicuous, 

 close-set. 



Deshayes, Pro. Zool. Soc. 1854. 



Ilab. ? 



A light flesh-tinged shell, quite distinct in its characters 

 from any other species. 



Species 76. (Mus. Brit.) 



Mactra Murchisoni. Mact. testa ovatd,submitricosd, 

 soliditcsculd, alba, lavigafd, epidermide stramined ver- 

 sus marginem indutd, subcequilaterali, latere antico 

 rotundato, postico sublongiore, leviter angulato-pro- 

 dudo, angulo lineari-carinato ; lunuld perampld, cor- 

 rugato-liratd ; umhonibus confertis. 



Murchison's Mactra. Shell ovate, subventricose, rather 

 solid, white, smooth, covered towards the margin 

 with a straw-coloured epidermis, nearly equilateral, 

 anterior side rounded, posterior rather the longer, 

 slightly angulariy produced, angle lineariy keeled; 

 lunule very large, wrinkle-ridged ; lunboes close-set. 



Deshayes, Pro. Zool. Soc. 1854. 



May, 1854. 



