﻿SONNINIA CRASSISPINATA. 317 



it is impossible to make any conjectures. This is the more curious because in 

 regard to other groups these questions can be answered with some degree of 

 success. 



Sonninia multi spin ata, S. Buckman. Plate L, figs. 11 — 13. 



Discoidal, carinate. Whorls depressed, subcircular, ornamented each side 

 with a single row of nearly equidistant spines placed almost on the edge of the 

 lateral and ventral areas. Faint single ribs lead to the spines ; and very 

 indistinct ribs, 1 in twos and threes, lead from the spines, to be soon lost amid the 

 ventrally-inclined growth-lines. Ventral area carinate-sulcate, broad, flat, but 

 more gibbous the older the shell. The carina apparently hollow, dividing a 

 noticeable depression, so that it is bordered each side by a sulcus. Inclusion 

 just to the spines. 



This peculiar species is, biologically, the earliest form of Sonninia with which 

 I am acquainted. That the specimen figured is not mature, but is the young 

 of a larger form, will probably be found to be the case : it is certainly 

 not the young of any species now in my cabinet. Its broad, sulcate-carinate 

 abdomen, its coronet of closely-packed, regularly-placed spines, and the extreme 

 faintness of ribbing distinguish it from any other species. The specimen figured 

 is unique. It came from the Concaoum-zone of Bradford Abbas. Side and front 

 views are represented in figs. 11 and 12 of PI. L, and part of the suture-line in 

 fig. 13. It will be noticed that the superior lateral lobe is outside the spine. 



Sonninia crassispinata, 8. BucJcman. Plate XLVIII, figs. 16, 17; Plate L, figs. 



16—22; Plate LVII; Plate LXV, figs. 

 3—5. 



1889. Sonninia acanthodes, S. Buchman. Descent of Sonninia ; Quart. Jo urn. 



Geol. Soc, vol. xlv, p. (358 (pars). 



Discoidal, compressed, hollow-carinate. Whorls ornamented with strong 

 spines; single ribs lead to the spines, and branches of two or three radiating 

 ribs generally lead from the spines. The spines are persistent up to adult age, 

 though they often fail in places, only single ribs being formed. Ventral area 

 1 Bather too prominent where shown in the figure. 



