12 nucxjliujE. 



subveiitricose, only gaping at the posterior tip, clothed with a 

 glossy olivaceous ash-coloured epidermis, devoid of an anterior 

 indented ray, everywhere (beaks excepted) concentrically and 

 somewhat shelvingly striated, or finely and closely grooved. 

 Anterior extremity rounded, a little tapering : posterior side an- 

 gularly projecting above. Dorsal slopes rather slight, little curved. 

 Ventral margin subarcuated in front, obliquely and somewhat 

 convexly rising (without indentation) at the hinder end. Beaks 

 smooth, central or very nearly so. Front dorsal area inconspicuous. 

 Escutcheon with pouting lips, angularly defined by the posterior 

 ridge, divided into two concave areas by a radiating linear an- 

 gulation ; outer one plicately wrinkled ; inner one nearly smooth. 

 — My description does not precisely agree with Mr. Adams's, but 

 both were drawn up from the unique example in Mr. Cuming's 

 collection. 



20. Jj. LATA., Hinds,?, ii, 45. — T. subsequilateralis, compressa, 

 oblongo-lanceolata, eburnea, polita, nisi postice et in medio su- 

 perne sulcis iuclinatis subremotis concentrice sculpta. Margo 

 dorsalis utrinque rectiusculus et vix declivis ; ventralis arcuatus. 

 Area lanceolata, subduplex ; interior sublsevigata, planulata ; ex- 

 terior concava, sulcis inclinatis oblique sculpta. Lunula planulata 

 et obHque striata. — Oblong-lanceolate, compressed, except at the 

 umboes, which are convex, or even subventricose, scarcely gaping, 

 of a polished ivory-white, smooth on the central umbonal region 

 and posterior third, elsewhere concentrically graven with rather 

 distant imbricating sulci. Anterior side slightly longer, its ex- 

 tremity a little attenuated, and unsymmetrically rounded. Pos- 

 terior side peaked ; the tip rather above the middle, with a short 

 dorsal retusion. Front dorsal edge nearly straight, scarcely sloping : 

 hinder dorsal edge straight or subretuse, a little sloping. Ventral 

 margin regularly arched, much rising at both ends (obliquely so 

 in front), devoid of retusion. Escutcheon lanceolate, well defined, 

 subbipartite ; the flattened top nearly smooth ; the concave lower 

 portion obliquely marked with distant imbricating sulci. Lunule 

 manifest, flattened, obliquely striated. Interior subiridescent. 

 Teeth very fine and numerous on both sides. The fry, which is 

 grooved throughout, reminds one in shape of navicularis. 



21. L. Belcheei, Hinds, L 53. — T. anguste oblonga, subeequi- 

 lateralis, postice sinuato-subtruncata, sulcis inclinatis subobliquis, 

 nisi postice, longitudinaliter sculpta. Kegio postica superior 

 inferne subito impressa, in medio lira vix elevata radiante divisa. 

 Margo dorsalis antice declivis et convexiusculus, postice incurva- 



