Interior unknown. 
Dimensions.—Length, 4.4; breadth, 2 mm. 
Locality.—-Vale Royal Vineyards, Happy Valley. 
Horizon.—Eocene: Glauconitie sandstone. 
Remarks.—The description has been made from a pseudo- 
morphous cast in glauconite. 
The species comes near to S. fenestratus, Tate; but differs 
from it by being a more stumpy shell, less acute anteriorly, 
and having a more rotund marginal outline posteriorly. 
The angle between the margin of the post-dorsal area and 
the dorsal line is less defined, and the ventral margin less | 
curved. The ribs are stronger and fewer in number. | 
I have had opportunity of showing the specimen to the 
late Professor Tate and Mr. J. Dennant, who agreed with 
me in its specific variation. 
