204 



the front, subtruncated at both ends ; left side swollen ; spire in- 

 €ompletely concealed, slightly exsert. 



Aperture narrow, margined with elongate teeth ; outer lip 

 slightly margined at the two extremities, shortly projecting 

 beyond the spire ; inner lip thickened posteriorly and confluent 

 with the outer lip, forming a very short canal ; front part of 

 ■columella much elevated internally, concave and ribbed. 



Surface of the shell smooth or marked with faint distant spiral 

 lines and obscure contusions. 



Dimensions. — Length, 37; width, 24; height, 21. 



Locality. — Eocene ; Muddy Creek. 



This fossil comes very near to C. Reevei, Gray, recent in S.W. 

 Australia, but is proportionately higher and consequently the 

 •slopes from the highest point are more rapid, the front is more 

 narrowed, whilst the swollen left-side gives it a distinctive lop- 

 sided profile. The corresponding measures of C. Reevei are 37, 

 22, and 19. 



3. Cyprsea subsidua, ><pec. now 



Shell oval- inclined to trapezoidal- oblong, depressedly convex, 

 obtuse at both ends ; the right side flatly rounded, the left more 

 arched and rather abruptly contracted to the front ; spire exsert. 



Aperture narrow, base rather flat; outer lip not margined, 

 broadly subplanulate medially, with about twenty-five stout 

 rounded ridges. Inner lip developed behind into a prominent 

 protuberance margining the short anal canal and posterior part 

 of the aperture, with about twenty acute ridges ; it is somewhat 

 flattened towards the front, and runs out into a narrow triangu- 

 lar extension of the base, supporting the very short, truncate, an- 

 terior canal. The columella is much elevated internally and very 

 •concave. 



The surface of the shell is smooth. 



Dimensions of a large example. — -Length, 26; width, 17'5 ; 

 height, 14. Of a small example, 18, 11-5, and 9. 



Locality. — Eocene ; Muddy Creek. 



The squat-form, flattish base and post-ventral protuberance dis- 

 tinguish this species from C. scalena., which from its undeveloped 

 appearance might be regarded as an inmature state of that spe- 

 cies. But the numerous examples under observation prove that 

 the adolescent feature is proper to the adult as it is in the living 

 C. Reevei and its fossil analogue C. scalena. Without comparison 

 of actual specimens, I am not sure if this be distinct from 

 C. BcLvtonensis, F. Edw,, of the English Eocene, though the Aus- 

 tralian shell appears different, by its large posterior boss and the 

 less prominent spire. 



