276 



G. 5571. Imperfect specimen, probably referable to this species; 

 pallus rather thick on the inner margin of the aperture. Post- 

 Pliocene : Limestone Creek, Glenelg river, Victoria. Purchased. 



Genus COLLONIA, Gray. 

 [Guide Syst. Dist. Moll. 1857, p. 143.] 



Shell globose, solid, not nacreous, smooth or spirally striated, 

 narrowly but deeply umbilicated ; spire depressed or short ; 

 aperture circular, peristome thick, thinnest where it reposes on 

 the penultimate whorl ; umbilicus typically crenulate at the border 

 and having a ridge interiorly. 



Type. — Delphinula marginata, Lamarck. 



Collonia parvula, Tenison- Woods (sp.). 



1880. Crossea parvula, Tenison-Woods, Proc. Linn. Soc. N.S.'W. vol. iv. 



p. 4, pi. i. fig. 7. 

 1893. Collonia parvula, Tate and Denuant, Trans. Roy. Soc. South Aust. 



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



Shell depressed, whorls faintly spirally striated, having a 

 moderately wide umbilicus, which is simple ; aperture circular, 

 solid. 



Dimensions. — Length 2 mm. ; breadth 3 mm. 



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



G. 9462. Several examples of the adult. Purchased. 



Family TROCHID^. 



Genus TROCHUS, Linnaeus. 



[Syst. Nat. ed. 10, 1758, p. 756.] 



Shell conical, spire elevated, whorls but slightly convex and 

 frequently flat ; last whorl keeled or angulate ; base concave, 

 broad ; aperture rhomboidal ; outer margin sharp, very oblique ; 

 with a more or less deep, false umbilicus ; columella twisted, 



