284 



aperture circular, peristome continuous, thick, with broad 

 marginal expansions ; umbilicus deep. 

 Type. — BelpMnula cancellata, Gray. 



Liotia roblini, Johnston. 



[Plate VIII. Figs, ^.a-c] 



1880. Liotia roblini, Johnston, Pap. Eoy. Soc. Tas. 1879, p. 39. 

 1885. liotia roblini, Tate, id. 1884, p. 211. 



1893. Liotia roblini, Tate and Dennant, Trans. Eoy. Soc. South Aust. 

 vol. xvii. pt. 1, p. 223. 



Shell small, with depressed spire; whorls rounded, trellised, 

 there being seven spiral threads on the penultimate whorl, 

 including those which border the suture and the umbilicus, the 

 interspaces being finely longitudinally striated, points of inter- 

 section of the longitudinal and spiral threads nodose ; aperture 

 circular ; peristome continuous, very thick, especially the basal 

 portion of the outer margin ; umbilicus deep, trellised. 



The shell is not solid, nor are the longitudinal ribs so large as 

 in X. gervillei, Defrance, of the Paris Basin, to which it bears 

 some resemblance. 



Dimensions. — Length 5'5 mm. ; breadth 6"5 mm. ; length of 

 aperture 2 "75 mm. 



Form, and Loc. — Eocene : Muddy Creek, Yictoria. 



G. 4301. Three examples of the neanic stage of growth. 



Presented hy John Dennant, Esq. 

 G. 9465. Series illustrating stages of growth. Purchased. 



Family HALIOTID^. 



Genus HALIOTIS, Linnseus. 



[Syst. Nat. ed. 10, 1858, p. 779.] 



Shell oval or oblong, nacreous; spire small, much depressed, 

 suture well marked ; aperture with continuous borders ; columellar 

 border broad, compressed, and arched; outer margin very oblique; 



