nuculida;. Ill 



ticus convexiusculus ; posticus subrectus, denique autem incurva- 

 tus. Arese sicut in L. creniferd. — Of a produced beaked-oblong 

 shape, very inequilateral, not very thin, compressed, whitish, 

 without an elevated umbonal ridge, with a well marked anterior 

 broadish indented ray, before which the very fine close-set longi- 

 tudinal wrinkles, which become raised and very oblique posteriorly, 

 are lamellar and more distant. Extremity of the much shorter 

 anterior side subangulated and more projecting above, obliquely 

 rounded below. Hinder side much and gradually attenuated, 

 beaked ; its recurved tip narrow, obliquely subtruncated. Dorsal 

 slopes very slight ; the front one plano-convex ; the hinder one 

 incurved. Ventral margin much rising at both ends, arching up 

 obliquely in front, convex behind. Beaks acute, scarcely pro- 

 minent. Dorsal areas as in crenifera. Cartilage-pit small, 

 sunken, triangular. Teeth very numerous, especially behind. — In 

 the largest only of the three individuals known to me (one of 

 which perchauce may be adult) do the oblique striae extend to the 

 crenated ridge. The ventral margin is slightly indented a little 

 beyond the middle, and just before its hinder termination. 



10. L. decora, A. Adams, f. 47, 4S. — T. subaequilateralis, 

 parva, valida, subanguste oblongo-rostrata, postice attenuata, 

 albida, liris concentricis tenuibus undique corrugata. Extremitas 

 rostri recurvati angusta, oblique subtruncata. Margo dorsalis 

 uterque vix declivis ; posticus incurvatus. Area ampla, depressa, 

 crenulato-marginata. — Of an elongated beaked-oblong shape, ra- 

 ther small, convex or subventricose, gaping slightly at both ends, 

 dull white, concentrically lyrated (the dorsal areas excepted) 

 throughout : the lyrated wrinkles very small and crowded, except 

 upon the umboes, upon a ray-like anterior portion (where they 

 are irregular and coarser), and along the umbonal ridge, which 

 latter is refuse in the middle, and undefined anteriorly. Sides 

 nearly equal ; extremity of the slightly shorter anterior one nar- 

 rowed, and symmetrically rounded : posterior side attenuated, 

 gradually beaked ; its tip narrow, recurved, obliquely subtruncated. 

 Front dorsal slope rather slight ; hinder dorsal slope slight, in- 

 curved. Ventral margin arched behind, straighter in front, sub- 

 retuse at its termination and very slightly so in the middle. Es- 

 cutcheon very large, depressed, creno-marginated. Lunule per- 

 ceptible, simple. Cartilage-pit very small, triangular, sunken. 

 Teeth moderately numerous on both sides. 



11. L. costellata, Sowerbi/, f. 59. — T. subanguste oblongo- 

 rostrata, compressa, subaequilateralis, liris remotis concentrice 



