﻿PLATE LXVII. 



Concavum-zone. 

 Figs. 1, 2. — Sonninia dominans, S. Buchman. 



Fig. I. — Side view of an immature example to compare with marginata 

 (PI. LXV). Natural size. Bradford Abbas. My Collection. (The ribs, espe- 

 cially those of the first three-quarters of the last whorl, are hardly sufficiently 

 conspicuous.) (Page 322.) 



Fig. 2. — Front view of the same shell. 



Figs. 3, 5. — Sonninia, intermediate form. 



Fig. 3. — Side view of a ribbed form which is, practically speaking, intermediate 

 between marginata and dominans. Natural size. Bradford Abbas. My Collec- 

 tion. The last three ribs are incorrectly drawn.) (Page 322.) 



Fig. 4. — Front view of the same shell. 



Fig. 5. — Parts of two suture-lines, showing the slightly unsymmetrical 

 trifurcate superior lateral lobe. 



