296 GASTROPODA. [Pectinibranc.hia. 



Distribution. Mostly Arctic and Antarctic. 



Fossil in the English Crag, Pliocene of New Zealand, and Pleis- 

 tocene of Canada. 



1. Trichotropis clathrata, Sowerby, 1874. Plate 44, fig. 9. 



TricJiotropis clathrata, Sow., Conch. Icon., six, pi. 2, f. 10 : Ereb. & Ter., 

 ii, 3, pi. 1, f. 21; Man. Conch. (1), ix, 43, pi. 7, f. 51. T. inornata, 

 Button, C.M.M., 26 ; M.N.Z.M., 69. 



Shell small, fusiform, thin, cancellate, narrowly umbilicate. Sculp- 

 ture consisting of prominent spiral threads, 3 of them upon the shoulder 

 of the whorls between suture and carina, and 3 more prominent threads 

 on the keel and below it on the spire-whorls, about 10 on the body- 

 whorl ; these are cancellated by slightly oblique and distant radiate 

 riblets, much less prominent than the spiral sculpture ; granulate at 

 the points of intersection ; a strong rounded carina bordering the 

 umbilicus. Colour cinereous ; dead shells yellowish-white. Epidermis 

 present only in fresh or living specimens, thin, horny, fringed upon 

 the ridges. Spire more or less elevated, conical, mostly of about the 

 same height as the aperture. Protoconch small, of I smooth and 

 globose whorl. Whorls about 5, angled, carinated above, the last of 

 very large size ; base slightly depressed around the beak. Suture 

 canaliculated. Aperture very large, vertical, subtrigonal. Outer lip 

 convex, slightly expanded in adult specimens, margin crenate. Basal 

 lip oblique, forming with the anterior end of the columella a short, 

 narrow, and open canal. Columella high, lightly concave, with a small 

 projecting angle at the base, then narrowing and forming the inner 

 margin of the canal. Inner lip strongly callous, narrowly reflected, 

 and joining above the outer lip. Umbilicus narrow, channelled. 

 Operculum horny, light brown, longitudinally striate ; apex anterior. 



Diameter, 10 mm. ; height, 16 mm. Angle of spire, about 40. 



Animal unknown. 



Type of T. inornata in the Dominion Museum, Wellington ; of 

 clathrata, in the British Museum. 



Hob. Throughout New Zealand, in deep water ; Chatham Islands ; 

 Bounty and Snares Islands, in 50 fathoms (Captain Bollons). 



Remark. Hutton's species having never been figured, Sowerby's 

 name has to be used. 



Fossil in the Pliocene. 



Genus 2. LIPPISTES, Montfort, 1810. 



Lippistes, Mtft., Conch. Syst., ii, 1810, 217. Type : Argonauta cornu, Gmel. 



(= Grayi, A. Ad.). Separatista, Gray, 1847 (type, Turbo separatista, 



Dillwyn) ; Fischer, Man. Conch., 690 ; Ad. G.R.M., i, 136 ; Hedley, 

 P.L.S. N.S.W., xxvii, 23. 



Shell subdiscoidal, with a short spire, the last whorl visually sepa- 

 rated from its predecessors, forming a very large umbilicus ; aperture 

 slightly channelled at the base. Operculum with apical nucleus. 



