MJCUUD.E. Jl 



rior side, which occupies about tHo-iifths of tlie total length, some- 

 what narrowed and almost syniMietricaily rounded. Posterior side 

 decidedly beaked, tapering rather quickly to a peculiarly small 

 and narrow bianguhited tip; umbonal ridge moderately broad, 

 flat, but well dctined by its horizontal iyrre, and its curved upper 

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

 retuse or incurved. Ventral margin decidedly arcuated, mucli 

 rising in front, distinctly retuse 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. Var. Ventricose, ovate-conic, usually with a few 

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

 tral margin peculiarly arched in front. Distinguished from ienui- 

 sulcafa by tlie shape of the rostrum. 



18. L. LUGUBRis, A. Adams, f. 7.5, 70. — T. insquilateralis, 

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

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

 lirffi crassa?, remotfe. Margo dorsalis posticus rectiusculus, valde 

 declivis ; ventralis anticus arcuatim acclivis ; cardinalis latus. 

 Arese dorsales laeves, magnse, detinitae. 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 subimbricatcd coarse concentric lyrje. 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-])it, but a short, 

 yet very manifest, external ligament. Locality unknown. Size 

 of a svaaW parva. Reminds one of a Crassatella. 



19. L. iNCONSPicuA, A. Adams, f. 77, 78. — T. aequilateralis, 

 oblongo-subconoidea, postice superne angulatim eminens, cute 

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

 tibus exceptis) sulcis tenuibus densis subinciinatis concentrice 

 striata. Margines dorsales subdeclives, vix curvati ; ventralis 

 antice subarcuatus. Area angulatim definita, duplex ; exterior 

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



