SMITH : ON MTJLLEKIA DALTI. 



15 



extreme margins of the lobes are of a dark-brownisli colour, and 

 very finely papillate within for a short distance ventrally from the 

 posterior extremity. 



The gills are unequal, the inner pair being somewhat larger than 

 the outer. The mouth is large, and the labial palpi are united dorsally 

 nearly their whole length. The body is produced into the branchial 

 cavity, and has a foot-like appearance, whilst the anal tube is just 

 above the large adductor as in ^theria,^ and, indeed, in all Pelecypoda. 



MuLLEEiA Dalti, n.sp. 



Testa irregulariter quadrata, sed postice producta at rotundata, 

 compressa, inaequivalvis ; valvse mediocriter crassse, intus margari- 

 tacese, iridescentes, olivaceo plus minus maculatse et ad marginem 

 olivaceo-fusco limbatse, extus sub periostraco subfibroso, nigro-fusco, 

 fortiter concentrice striate, ex laminis albis calcareis et aliis cornels 

 fuscescentibus constitse ; valva adhserens irregulariter planata, altera 

 convexior, plus minus erosa ; cicatrix musculi posterioris magna, 

 elongata vel rotundata, mediocriter profunda, concentrice et radiatim 

 striata ; linea pallii irregularis, punctata, ad marginem superiori fere 

 attingens ; margo dorsi rectus, ligamento valido per totam longitudinem 

 instructus. Long. 65, alt. 52, cliam. 20 mm. 



1 Quoy in Lesson's lUust. Zool., pi. lix ; Rang & Cailland, Mem. du Mus., ser. iii, 

 vol. iii, p. 143, pi. vi ; Deshayes, Anim. sans Vert., vol. vi, pp. 591-6. 



