316 



The Gastropods of the Older tertiary of 

 Australia. 



Part IV. (including Supplement to Part III.). 



By Professor Ralph Tate. 



[Read OctoLer 17, 1893.] 



Plates VI. -X. 

 FAMILY CYPR.EID.E. 



Cyppsea Mulderi, Tate. 



(Trans. Roy. 8oc. S. Aust., vol. XIII., 1892, pi. ix., f. 4 ; 

 without descrij:)tion. ) 



Shell depressedly globose, spire concealed ; basal outline 

 oblong ; back almost circular in basal outline, polished, marked 

 with circular contusions varying from 4 to 5 mm. in diameter. 

 Anterior canal abruptly upturned, flanked on each side by a 

 broadly-triangular, slightly concave, thickened extension of the 

 base. Posterior canal short, with very wide flanges, the left one 

 more extended than the right. Base nearly flat, much thickened ; 

 outer lip excessively inflected, rounded, its inner margin set with 

 nearly equal and somewhat slender rounded ridges ; inner lip 

 with a broad convex area steeply sloj^ing inwards, the anterior- 

 third furnished witli about seven ridges narrower than the inter- 

 vening sulcations, the rest of the lip edentulous. 



Dimensions. — Total length, 100 mm.: width, 64 mm.; height, 

 50 mm.; length of Imck, 66 mm. 



Localities. — ^Eocexe ; in a well-sinking at Belmont, near 

 Geelong, one example, collected and presented by Mr. Mulder, 

 to whom the species is dedicated ; Bellarine Peninsula (Hall and 

 Pritchard). 



Affinity. — This species comes near to C. jilatypyga, IMcCoy,^ 

 but the back is not pyriform, the anterior canal much reflected, 

 and the shape of the base and details of the aperture are 

 different ; otherwise it might be regarded as a senile form of that 

 species. 



SuBCiENUS CvPRiEDiA, Sivainsou, 1840. 



Dorsal surface with revolving threads or tessellated ornament. 

 Distinguished from Cyprfeovula, Gray, 1824, by the absence of a 

 posterior apertural notch. One living species, C. cancellata, is 

 known, and there are fi^ e in the European Eocene. 



