331 



and gently rounded Itjngitudinally ; surface with fine growth- 

 lines ; beak hooked, posterior, projecting beyond the posterior 

 margin. 



Dimensions. — Length, 14 ; breadth, 8 ; height, 5 '5 mm. 



LocaHty. — Eocene : Table Cape (J. M. Johnston). 



Genus Calytraea. 

 synopsis of species. 

 Axis imperforate (Calyptraea, s.s.). 

 Shell depressed, apex subcentral. 



Concentrically corrugated, interruptedly convex. 



1. Qorriigata. 

 Concentrically lamellose-striate, regularly convex. 



2. placuna. 

 Spire elevated, apex lateral or subcentral. 



AVhorls ventricose, posteriorly flattened. 3. subtabulata. 

 Whorls regularly convex. 



Spire narrow-conic ; finely lamellate-striate concentrically; 

 spirally -lined. 4. undidata. 



Spire broad-conic ; concentrically lamellose. 



5. crassa. 

 Axis umbilicate (Calyptropsis) depressedly convex, apex very 



excentric. 

 Body-whorl ventricose ; base subcircular. 



Concentrically lined, radially lined and striated. 



6. arachnoideus. 

 Body-whorl flatly sloping posteriorly. 



Base subcircular, slender radial and concentric threads. 



7. tnrbinata. 

 Base oval, radially costated, flnely lamellose, striated con- 

 centrically, body-whorl much depressed. S. umbilicata. 



1. Calyptraea eorrugata, -^j^fic. nor. Pi. vii., flg. 9. 



Shell depressed, orbicular in basal outline, sub-pellucid ; body- 

 whorl more or less ventricose around the suture, surface irregu- 

 larly concentrically i-idged : edge of septum slightly arched. 



Similar to C. pelliicida, Reeve, with specimens of which I have 

 compared it ; but differs by interruptedly-convex whorls and 

 strong growth-folds. 



Dimensions. — Basal diameters, 12 and 11 : height, 3-5. 



LocalifAes. — Miocene : Muddy Creek and at Xor'-west Bend, 

 River Murray. 



2. Calyptraea plaeuna, -^px-. nor. Pi. vii., tig. 4. 



Shell depressed, thin, fragile, orbicular in basal outline ; l)ody- 

 whorl regularly convex, anterior surface slenderly lamellate con- 

 centrically, becoming posteriorly striate. 



