PLANAXIS. 173 



deflexo; margine intus incrassato, liratim dentato. — A smooth, 

 pyramidal, thick white shell, with a velvety epidermis. 



11. DECOLLATCS (Quoyia), f. 2, Gray. — Fulvus et griseus, 

 leviter strigatus, elevatim pyramidatus, spiraliter valide sul- 

 catus ultimo anfractu obtuse angulato ; apertura subtrigona ; 

 columella crassa, postice excisa et unidentata, antice truncata, 

 labro prope suturam subdepresso, antice rotundatim expanse. 

 — The apex appears to be deciduous, and the columellar lip, 

 which in most sliells of the genus Planaxis has a little callus 

 near the suture, is so notched out as to leave a sort of tooth. 

 This seems hardly a sufficient difference to justify generic 

 separation. 



12. MicnAUDi (Quoyia), f. 1. — Pyramidatus Lnevis acumin- 

 atus ; apertura trigona, margine crenato, columella tenui ; 

 postice exciso et unidentata. — This species is smaller and 

 smoother than sp. 11. — It does not lose its apex, while 

 the notch and tooth on the columella are not so con- 

 spicuous. 



13. NUCLEUS, f. 20, Lamarck. — Breviter bulbiformis,'acu- 

 minatus niger crassus ; ultimo anfractu magno infra rotundo, 

 prope suturam infra medium et ad marginem externum 

 apertura profunde sulcato ; apertura infra expansa, margine 

 crasso crenato ; columella prope suturam canaliculata. — 

 Smooth in the centre of the whorls, but sulcated deeply at 

 the top and bottom. 



14. NiGRiTELLUS, f. 21, Fovhes. — Quam P. nucleus magis 

 pyramidatus, sulcis baud profundis, medio anfractuum eva- 

 nidis. — More pyramidal than P. nucleus, with the grooves 

 slighter, and disappearing in the middle of the whorls. 



15. ATROPURPUREUS, f. 10, Kvauss. — Lcevis niger; anfrac- 

 tibus ad suturam plumbeo-fasciatis, infra leviter trisulcatisi. 

 — Having a little lead-coloured band under the suture, and 

 faint grooves on the lower part of the whorls. 



16. LABIOSDS, f. 25, Adams. — Subpyramidatus Isevis nigro- 

 fusca, nigro obscure spiraliter fasciata. — A dark shell, with 

 darker cross-lines. 



17. ACUTus, f. 35, Krauss. — Acute pyramidatus, niger; 

 anfractibus supra infraque tenuiter sulcatis ; apertura ad 

 marginem lirata. — More sharply pyramidal than the pre- 



