nuculidjE. 159 



olive ; scarcely smooth, the faint striae of growth being here and 

 there almost regular. Anterior extremity well rounded, front 

 dorsal slope at first slight, convex. Ventral margin entire, much 

 arcuated, rising obliquely behind, forming a rather obscure obtuse 

 angle with the abrupt slope of the very short posterior side. 

 Beaks acute, not prominent. Lunule small, concentrically striated, 

 flatly impressed below, pouting above. Front dorsal area not de- 

 fined, but prominent. Nacre bluish. 



28. N. convexa, Sowerhj, f. 112, 113.— T. oblique ovata, 

 longitudine latitudinem multo superante, valida, concentric^ cor- 

 rugato-subplicata. Latus posticum hand perbrevis, fere in medio 

 angulatum. Margo dorsalis anticus prope nates prominentes rec- 

 tiusculus vixque declivis, deinde curvatus satisque declivis ; 

 posticus brevis, demum retusus. Margo ventralis integer, multum 

 arcuatus, postice notabiliter oblique acclivis. Lunula brevis, satis 

 circumscripta, planulato-impressa, cordata. Area fere inconspicua. 

 Margo cardinalis latus : dentes circiter 22-7 : cartilago subhori- 

 zontalis. — Obliquely ovate, much longer than broad, strong, sub- 

 pliciformly corrugated concentrically. Anterior side rounded at 

 the extremity (sometimes a little taper) ; its dorsal slope at first 

 straightish and nearly horizontal, then curved and moderately 

 sloping. Posterior side not short for the genus, subcentrally an- 

 gulated, its dorsal slope short, not very abrupt, eventually refuse. 

 Ventral margin entire, much arched, very conspicuously slanting 

 upwards behind. Umboes prominent. Lunular area tolerably 

 defined, flatly impressed, short, cordiform. Front dorsal area a 

 little indented, undefined. Hinge-margin broad ; cartilage sub- 

 horizontal : teeth little raised, about twenty-two and seven (in the 

 aged), very close, wide, and obtusangular. — The epidermis of the 

 adult is unknown, but it is cinereous and shining in the fry, 

 which is at that stage smooth, with its lunule projecting in the 

 middle.* 



29. N. antipodum, Eanley, f. 155. — T. valde obliqua, ellip- 

 tica, postice recte truncata, antice rotundato-attenuata, maxime 

 insequilateralis, valida, subventricosa, laevis, cute nitida pallide 



* la the ' Proceedings of the Boston Society of Natural History ' (ii. p. 100), Dr. 

 Gould refers to N. tumida of Reeve (? a slip of the pen) as resembling his — 



N. turgida. — " T. alba, subiequilateralis, subrhomboidea, postice acuta, antice ro- 

 tundata, vcntricosa, margiue ventrali pendente, ubique lamellis concentricis obtusis 

 reflexis confertis ornata : natibus promiuentibus ; cardine dentibus 21 utroque latere 

 instructo. §-i." No locality is mentioned, but the description is included in his 

 accouut of Tavoy land and fresh-water shells. From the dentition and lamellation I 

 should have thought it a Leda rather than a Ifucula. 



