8 NUCULID.«. 



lamellosa, cristis binis squarniferis postice radiata. Extremitas 

 rostri postici angust;i, biangulata. Margo ilorsalis uterque vix 

 declivis ; posticus incurvatus. Labia arefe magnje, Isevis, coucavre, 

 protrusa. — Peaked elongated-oblong, rather thin, compressed, 

 under an ashy or pale olivaceous ash-coloured epidermis glossy 

 white, concentrically traversed by distant erect lamellie, which ter- 

 minate just before an umbonal ridge that is formed by two crest- 

 like squaraose ridges enclosing between them a flattish and nearly 

 smooth area ; intervals of the lamellae unsculptured. Extremity 

 of the moderately yet decidedly shorter anterior side attenuated, 

 and unsymmetrically rounded : hinder side gradually beaked ; the 

 tip fine, biangulated, subcentral. Front dorsal slope very sliglit, 

 plano-convex ; hinder dorsal slope rather slight, incurved, rising 

 at the extremity. Ventral margin arcuatedly rising in front, less 

 so behind, slightly indented before the posterior tip. Escutcheon 

 large, smooth, concave, yet with pouting lips. Lunule linear, 

 smooth, conspicuous. Teeth on either side of the very small 

 triangular cartilage-pit very numerous. — The epidermis is occa- 

 sionally iridescent. A more or less obsolete anterior indented ray 

 is generally perceptible. 



12. L. coNCiNNA, A. Adams, f. 54, 5.5. — T. lanceolata, postice 

 attenuato-rostrata, antice superne subangulata, valde inaequilate- 

 ralis, multum compressa, cute tenui cinereo-virescente induta, 

 concentrice lamellosa ; lamellae superne remotiores. Margo dor- 

 salis anticus rectiusculus, vix declivis ; posticus retusus, leviter 

 declivis. Areae dorsales elongata?, Iceves, impressae, angulatim 

 circumscriptae ; labiis jirotrusis. — Lanceolate, very inequilateral, 

 subangulated dorsally in front, attenuatedly beaked behind, rather 

 thin, much compressed, only gaping at the very narrow biangu- 

 lated and scarcely upturned posterior tip, covered with a thin 

 greenish-cinereous epidermis, devoid of marked anterior indented 

 ray, with a narrow umbonal ridge, which is subspinosely keeled 

 on either side. General surface concentrically lamellated ; inter- 

 vals of the lamellae, which are much more remote on the umboes, 

 and somewhat more distant in front, smooth. Eront dorsal slope 

 slight, nearly straight ; hinder dorsal slope rather slight, refuse. 

 Ventral margin obliquely arching upwards in front, convex and 

 moderately rising behind, retuse before the posterior tip. Dorsal 

 areas elongated, smooth, angularly defined, impressed, but with 

 the lips pouting. 



13. L. TENDisuLCATA, Couthouy, f. 87. — T. L. pernula assi- 

 milis, sed minor, radii impressi fere vel omnino expers, cute lutea. 



