MACTEA.— Plate XXL 



Hab. ? 



A thin swollen peUucid-white shell, truncated and gap- 

 ing at the posterior end, with very much the aspect of an 

 Anatina. 



Species 134. (Mus. Cuming.) 



Mactra pellicula. Mact. testa abbreviato-ovatd, iii- 

 (equilaterali, antice rotmulata et tumidd, podici ros- 

 tratd et truneatd, Idante, tenuissimd, pdliicklo-albd, 

 suhriide striata ; umbonlbus parvis, acutis. 



The pellicle Mactra. Shell shortly ovate, inequila- 

 teral, anteriorly rounded and swollen, posteriorly 

 beaked and truncated, gaping, very thin, pellucid- 

 white, rather rudely striated; umboes small, sharp. 



Deshayes, Pro. Zool. Soc. 1854. 



Jlai. Japan. 



Of a thin transparent pellicle-like substance, of a shorter 



and more beaked form than that of the preceding species. 



Species 135. (Mus. Cuming.) 

 Mactra Nuttallii. Mact. testa ovatd, plano-compressd, 



inaquilaterali, pellucido-albd, concentrice tewuiswlcatd 

 et striata, striis Jlexuosis radiantibus minutissimti caii- 

 cellatd ; latere antico nmllo majore, siiperiie declivi- 

 angulato, postico coarctato, compresso-rostrato, cari- 

 nato, Idante, extremitatibus lamellato-recurvis ; lunula 

 perampliter cordatd ; mnhonibus parvis, acutiitsculis. 



Nuttall's Mactra. Shell ovate, flatly compressed, in- 

 equilateral, transparent white, concentrically finely 

 grooved and striated, very minutely cancellated mth 

 flexuous radiating stri:e ; anterior side much the 

 larger, angularly slanting at the upper part, posterior 

 side contracted, compressly beaked, keeled, gaping, 

 with the extremities lamellarly recurved ; lunule 

 largely cordate ; umboes small, rather sharp. 



Lntraria (Cyptodou) Nuttallii, Conrad, Journ. Acad. Nat. 

 Sci. Philadelphia, vol. vii. p. 335. pi. 18. f. 1. 



Mactra reciirva. Gray in Wood Index. Test. Supp. 



Hah. South Carolina. 



A very characteristic transparent white compressed 

 species, peculiarly contracted on the posterior side, with 

 the extremities lamellarly curved outwards. 



