REPORT ON THE LAMELLIBRANCHIATA. 189 



This is a less convex species thau Lucina hulhda, rather longer, more pouting in 

 front, more equilateral, and has a much longer lunule. The radiating sculpture also is 

 more distinct, the ligamental groove broader, and the anterior muscular scar twice or 

 three times as broad. 



Cryptodon hullulus (Eeeve). 



Lucina bullula, Eeeve, Conch. Icon., vol. vi. fig. 35. 



Habitat. — Amboina, in 15 to 20 fathoms (Challenger) ; Port Essington (J. B. Jukes 

 in Brit. Mus.). 



The distribution of this species has not been previously recorded. The figure in 

 the Conchologia Iconica does not represent the adult form of it, for in the British 

 Museum there is a specimen from Port Essington which is 17 mm. long, 15 high, and 

 12 in diameter, and the single left valve from Amboina is even a little larger. 



This is a very thin species, slightly lunuled, considerably convex, rather shouldered 

 above and prominently curved along the lower margin. It is sculptured with fine lines 

 of growth and indistinct traces of radiating substria;. The toothless hinge-line is very 

 thin, and consequently the longish ligamental groove is very narrow. The anterior 

 muscular impression is remarkably narrow, and descends obliquely within the pallial line. 



Cryptodon moseleyi, n. sp. (PI. XIV. figs. 2-2a). 



Testa tenuissima, ovata, valde iua;quilateralis, mediocriter convcxa, semipellucido- 

 alba, haud nitida, incrementi lineis tenuibus striata, epidermide tenui pallide olivacea 

 prope marginem induta. Marge dorsi ante umbones elevatus, arcuatus, postice obliquus, 

 rectiusculus. Margo ventralis paulo curvatus, latum posticum versus obhque ascendens. 

 Umbones parvi, vix supra marginem producti, post medium siti. Cardo edentulus. 

 Ligamentum internum obliquum, pone apicem locatum. Pagina interna subuitens, 

 plus minusve radiatim substriata. 



This is an excessively fragile shell, broadly ovate, very inequilateral, the anterior 

 side being both longer and broader. It is moderately convex, of a dirty white colour, 

 not glossy on the surface, and clothed to some extent with a very thin pale olive 

 epidermis, especially towards the dorsal margin. The sculpture consists of fine Lines of 

 growth, some here and there being rather more conspicuous than the rest. The front 

 dorsal margin is arched and higher than the beaks, the posterior, on the contrary, being 

 shorter, straightish, and obliquely sloping. The anterior end is regularly semicircularly 

 curved, the posterior rather more obtusely arcuate, and the curve of the ventral margin 

 gentle and slowly ascending Ijehind. The umbones are small, scarcely elevated above 



