PLATE OIL 



Concavum-zone . 

 Figs. 1 — 3. — Sonninia costigera, 8. BucJcman. 



Fig. 1. — Side view of an adult example reduced to three-fourths of natural 

 size. (The central whorls are badly preserved and damaged by the tool.) In 

 order to show the characters of the specimen some details have been taken from 

 the other side to supplement this view. The umbilicus is drawn slightly too large so 

 far as its ultimate and penultimate turns are concerned. Bradford Abbas. My 

 Collection. (Page 428.) 



Fig. 2. — Outline of the whorl-section reduced to three-quarters of natural size. 



Fig. 3. — Portion of the suture-line from the same fossil, showing an axial but 

 anisosceloid terminal lobule to L. 



