NUCULlDiE. 157 



baud sinuatus, intus subinteger (minutissiine crenulatus) ; cardi- 

 nalis valde latus. Nates acuta?. Lunula baud sculpta, profundi 

 circumscripta : area subinconspicua. Dentes antici permulti ; 

 postici perpauci. Fossa cartilaginis angusta, obliqua. — Large, 

 strong, oblique, ovate, scarcely ventricose, smootbish or with 

 coarse incremental wrinkles in front, very inequilateral, not colour- 

 rayed, silvery-white witbin, simply rounded in front, rotuudately 

 angulated below bebind. Front dorsal edge convex, not remark- 

 ably sloping ; binder slope decided, straigbtisb or subretuse, 

 .>iiiuated by tbe profound concavity which defines the lunule. 

 Ventral margin arcuated, devoid of a sinus, not distinctly crenu- 

 lated within, yet most minutely so at the outer edge. Beaks 

 acute, not much elevated. Hinge-margin very broad : front teeth 

 very numerous ; hinder ones very few : cartilage-pit narrow, 

 moderately slanting. — I am indebted for the recognition of this 

 species to M. Chenu, who having delineated the type for his beau- 

 tiful ' Manuel/ kindly forwarded me tbe unpublished woodcut. 

 The epidermis ranges from shining olivaceous-yellow to dark ashy- 

 obve. 



24. N. Ccmingii, Hinds, f. 117. — T. ovali-elliptica, baud 

 ventricosa, laevigata, lineis incrementi subpliciformibus tantum 

 ornata, cute nitidissima pallide olivaceo-virente induta. Extre- 

 mitas antica subattenuate rotundata, superne subemarginata; 

 postica rotundato-acuminata, et longior quam in Nuculis aliis. 

 Margo ventrabs integer, fere semicircularis, postice subsinuatus. 

 Lunula parva, lanceolata, planulata. Area permagna, prominens, 

 retusione sulciformi circumscripta. — Oval-elbptic, only subventri- 

 cose, everywhere smooth, except for tbe subpliciform wrinkles of 

 increase, with a polished pale greenish-olive epidermis. Anterior 

 extremity somewhat tapering, rounded, subemarginate above, front 

 dorsal slope convex and nearly horizontal. Posterior side long for 

 the genus, rotundately peaked, the peak subcentral, the somewhat 

 refuse dorsal slope not being abrupt as usual. Ventral margin 

 entire, almost semicircular, with a sbght refusion near its posterior 

 extremity. Lunule small, lanceolate, flatly impressed. Lozenge 

 large, prominent, well and concavely defined in the adult. Teeth 

 usually six and eighteen. 



25. N. Grayi, IfOrUgny, i. 126.— T. ovalis, longitudine lati- 

 tudinem multo superante, subventricosa, lsevis, cute nitidissima. 

 olivaceo-virente (rarius olivaceo-fuscescente) induta, antice sub- 

 attenaate, postice subangulatim, rotundata. Latus posticum haud 

 perbreve. Margo dorsalis antice convexus, prope nates baud emi- 



