NUCUUD I .. 115 



rior side, which occupies about two-fifths of the total length, some- 

 what narrowed and almost symmetrically rounded. Posterior side 

 decidedly beaked, tapering rather quickly to a peculiarly small 

 and narrow biangulated tip ; umbonal ridge moderately broad, 

 flat, but well defined by its horizontal lyrse, and its curved upper 

 edge. Dorsal slopes moderate, the front one convex, the hinder 

 refuse or incurved. Ventral margin decidedly arcuated, much 

 rising in front, distinctly refuse before the hinder termination so 

 as to abruptly pinch up the subcentral (and somewhat cocked-up) 

 tip of the rostrum. Lips of the escutcheon, which is large, and 

 clearly defined by an almost carinated rim, pouting. Lunule in- 

 conspicuous. Tar. Veutricose, ovate-conic, usually with a few 

 radiating lines on the umboes ; dorsal slopes very decided ; ven- 

 tral margin peculiarly arched in front. Distinguished from lenwi- 

 salcata by the shape of the rostrum. 



18. L. lugubris, A. Adams, f. 75, 7G. — T. infequilateralis, 

 ventricosa, ovato-trigona, postice subrostrata et obtuse cuneifor- 

 mis, cute olivaceo-tenebrosa induta, undique concentrice lirata : 

 lirse crassa3, rernotse. Margo dorsalis posticus rectiusculus, valde 

 deelivis ; ventralis anticus arcuatim acclivis ; cardinalis latus. 

 Area? dorsales laeves, magme, definitse. Dentes magni, pauci.— 

 Triangular-ovate, solid, ventricose, devoid of an umbonal ridge, 

 clothed with a dusky yellowish-olive epidermis, regularly sculp- 

 tured throughout (the large, smooth, well-defined, dorsal areas 

 excepted) by remote subimbricated coarse concentric lyrse. An- 

 terior side filling from two-fifths to three- sevenths of the total 

 length, contracted and rounded at the extremity. Posterior side 

 bluntly wedge-shaped, briefly and obscurely beaked. Hinder dor- 

 sal slope very decided, straightish ; front one moderate, at first 

 straight, then curved. Ventral margin much arched and rising 

 in front ; straighter behind. Beaks acute, reflected, prominent. 

 Escutcheon well defined. Lunule subcordiform. Hinge-margin 

 very broad ; teeth few, very large. No cartilage-pit, but a short, 

 yet. very manifest, external ligament. Locality unknown. Size 

 of a small parva. Eeminds one of a GrassateUa. 



19. L. inconspicua, A. Adams, f. 77, 78. — T. eequilateralis, 

 oblongo-subconoidea, postice superne angulatim eminens, cute 

 nitida olivaceo-cinerea induta, radio baud impressa, undique (na- 

 tibus exceptis) sulcis tenuibus densis subinclinatis concentrice 

 striata. Margines dorsales subdeclives, vix curvati ; ventralis 

 antice subarcuatus. Area angulatim definita, duplex ; exterior 

 plicato-corrugata. — Oblong-subconoid, moderately strong, merely 



