NUCULID^. 31 



become finer and peculiarly approximate near the ventral margin. 

 The specimen referred to in the ' Zoological Proceedings ' as in 

 Mr. Cuming's Museum, proves essentially distinct. 



51. L. HiNDSii, Eanley, f. 102. — T. parva, suba;quilateralis, 

 an^ustc ovato-acuta, antice plica sulcoque late radiata, postice 

 costa umbonali carinatii, superficiem la;vigatam supcriorem se- 

 quente, munita, alibi coucentrice costellata; interstitia liris minutis 

 undique decussata. Extremitas postica acuminata, vix recurvata. 

 Area magna, concava, arete longitudinalitcr costellato-striata ; in- 

 terstitia impressa punctulata. Lunula parva, transversim tuber- 

 culata. — Very small, subequilateral, pointed, ovate-oblong, more 

 or less ventricose, only gaping at the hinder tip, with a conspi- 

 cuous broad anterior indented ray and fold, white, concentrically 

 costellated, except a smooth upper space before the keeled or 

 sharply angulated umbonal ridge ; riblets regular and numerous, 

 scarcely as broad as their intervals, which are everywhere traversed 

 by minute radiating lyrse. Anterior extremity attenuatedly rounded: 

 posterior side, if either, the longer, simply and sharply acuminated, 

 the tip subcentral, acutaugular, scarcely, if at all, recurved. Dor- 

 sal slopes moderate ; front one convex ; hinder one straightish or 

 subretuse. Ventral margin arcuated in the front and middle, 

 rising at both ends, straighter behind. Lunule small, narrow, 

 subgranosely cross-barred : escutcheon large, concave, crowded 

 with longitudinal costellar strite, whose intervals appear punctulate 

 from the minute transverse sculpture. About a dozen teeth on 

 either side of the minute cartilage-pit. — Mr. Hinds had confused 

 this rare little shell (of which Mr. Cuming, Mr. Metcalfe, and 

 myself, each possess a single individual) with his N. crispa, which 

 name has been retained for the delineated species. An incipient 

 ridge almost renders the larger dorsal area a double one. I have 

 seen no epidermis. 



5-2. L. EXCAVATA, Hinds, f. 104., 105. — T. late ovato-rostrata, 

 subfequilateralis, ventricosa (vel tumida), antice late rotundata, 

 costa umbonali prominente angusta ornata, lamellis concentricis 

 (quarum interstitia latiora sunt haudque insculpta) undique cos- 

 tata. Extremitas rostri subiti perangusta, obtuse acuminata 

 multumque recurvata. Margo dorsalis posticus declivis, incur- 

 vatus ; ventralis antice multum arcuatus, postice valde acclivis. 

 Area maxima, excavata, superne longitudinalitcr costellata. Lu- 

 nula transversim costellata. — Of a rather oblique sharply-beaked 

 abbreviated ovate shape, ventricose or tumid, with a narrow 

 sharply elevated umbonal ridge (preceded by a slight retusion) 



