NUCULIU.E. 



29 



two perfect iiulividuals (Mus. Cuming), wlucli I have carefully 

 compared with the larger known species from suspicion of their 

 being immature. In the larger and apparently adult one, the 

 front dorsal area is traversed by a kind of interrupted flexuous 

 continuation of the ribs : this sculpture is not perceptible on the 

 younger example. The dorsal lips protrude. 



48. L. viTEEA, IfOrUgny, f. 170.— T. perparva, ovali-acuta, 

 postice repente acuminata," subsequilateralis, alba, radn irapressi 

 expers, undique arete et concentricc costellata. Margo dorsahs 

 antice convexus vixque declivis ; postice declivis, rectiusculus, 

 sed demum incurvatus ; ventralis multum arcuatus, postice autem 

 rectior multumque acclivis. Area magna, concava, angulatim 

 definita, longitudinaliter lamelloso-rugosa. Lunula trausversim 

 costellata, aliter inconspicua. Dentes magni, utrinque satis sub- 

 ffiqualiterque pauci.— Peaked-oval, more or less ventricose, scarcely 

 at all gaping, snow-white, glossy, not pellucid, without anterior 

 indented rav or marked umboual ridge. General surface most 

 closely, evenly, and prominently costellated throughout ; the costal 

 interstices mere simple sulci. Sides very nearly equal : the ante- 

 rior, if either, the longer, slightly tapering to a rounded extremity: 

 posterior side quickly and simply acuminated, its tip sharp and 

 subcentral. Front dorsal slope slight, convex: hinder dorsal slope 

 decided, nearly straight, eventually incurved. Ventral margin, 

 for the most part, much arcuated, yet straightish and rising con- 

 siderably behind, without marked posterior retusion. Escutcheon 

 lar^e rather excavated, lamellately wrinkled lengthways, sharply 

 an°uiated at its circumference. Lunule transversely costellated, 

 otherwise ill-defined. Hinge-margin broad ; the large teeth nearly 

 equally (and but moderately) numerous on either side of the ex- 

 tremely minute cartilage-pit.— D'Orbigny's types in our national 

 collection have been the source of this description. 



49. L. Jamaicensis, JfOrhigny, f. 173.— T. minima, subsqui- 

 lateralis, subovato-rostrata, ventricosa, radio impresso lato aiitico 

 plicaque umbonali angulari (retusionem profundam sequente) con- 

 spicue ornata, undique costellis iuterstitiisque lationbus concen- 

 tricc run-osa. Extremitas rostri subiti valde prommens multum- 

 que aciUangularis. Margo ventralis arcuatus, bisinuatus. Area 

 magna, subduplex ; superne sublongitudinaliter corrugata; inter- 

 ne concava, lamelloso-costata, carina umboiuxli circumscripta.— 

 Beaked-subovate, minute, ventricose, whitish, more or less glossy, 

 with a verv conspicuous broad indented anterior ray and a more 

 or less cariaatelv angular umbonal ridge preceded by a deep 



