321 



moderately convex (being slightly less convex medially) ; surface 

 marked with slightly sinuous growth-lines (passing into some- 

 what wrinkled threads at the suture and at the umbilical margin) 

 and interstitial line stride, and by inconspicuous revolving threads 

 and towards the suture by line strite. Aperture semi-lunaj", 

 oblique ; outer lip thin, slightly sinuated (projecting slightly 

 forward in an alignment with the inner edge of the callus ; 

 oolumellar callus narrowly and liatly spreading, tilling the narrow 

 umbilicus except a conspicuous groove leading into it from the 

 front. 



Dimensions. — Length, 19; breadth, 14; diameter of aperture, 

 l'2'O ; radius of aperture, 7 '5. 



Locality. — Eocene ; " Crassatella-beds " at Table Cape, Tas- 

 mania ! 



Remarks. — In 1876 Tenison- Woods recorded a not uncommon 

 Natica in the Table Cape beds as N. ovata, Hutton. I fail to 

 find any such species among the various collections examined 

 from that locality, and conclude that the subsequently described 

 species, iV. vix-umbilicata, was mistaken for it. Johnston 

 (''Geol. Tasmania," 1888), however, retains both names. 



X. vix-umhilicata is very much like X. ocata, Hutton. Com- 

 pared with specimens of the latter from the Pareora River 

 (Hutton's figure of this species, " Pliocene Moll, of New 

 Zealand," in Macleay Memorial Volume, 1893, tab. 7, tig. -±0, 

 very imperfectly represents the shell obtained from the lower 

 horizon), the present species is of much smaller size, slightly 

 narrower, of fewer whorls, apex immersed, callosity not so ex- 

 tensive, and by the presence of an umbilical chink. 



Among recent species, it has analogy with y. coiiica, but has 

 not the elongate spire of that shell ; but more so with iV. mam- 

 milla, from which it differs l^y regularly convex body-whorl, 

 proportionately wider. 



5. Natiea balteatella, ^ptc. nov. Pi. vi., fig. 7. 



Shell solid, narrow-oval-conic ; whorls five, moderately convex, 

 suture concealed by a thin adpressed extension from anterior 

 whorl. Surface smooth, shining ; ornamented by growth-lines 

 (which are abruptly bent and develop into wrinkles on the ante- 

 sutural band), coincident striiie and distant spiral stride ; a 

 broadish band in front of the suture is conspicuously wavy- 

 striated spirally, the spiral strite being interrupted l)y the sharply- 

 angled growth-folds, and by coincident strite. 



Aperture oval, outer lip acute ; columella emitting a funicular 

 ridge into the umbilicus, posterior callosity moderate. 



Dimensions.—LQugth, 18-5; wddth, 7-5; diameter and radius 

 of aperture, S'O, 6 -5 ; width of umlDilicus, 2. 



