EXPLANATION OF PLATE XXXI. 



Criockkas jackii, Elh. fil. 



Fig. 1. Lateral view of a fine partly testaceous specimen with obtuse 

 rounded costa 1 in the earlier stages, becoming more angular with 

 growth ; tubercles are not visible. 

 ,, 2. Dorso-ventral view of Fig. 1, displaying the overhanging whorls, 

 convex venter, and broad oval section. 



(Figures slightly more than half natural size.) 



