SPH EZRULITES. 431 
shells of the former genus in having only one internal 
longitudinal ridge, and in the external surface being 
roughened by irregularly raised plates, as in Lign. 138, 
jig. 1, which is a specimen from the Pyrenees, collected 
by M. Alex. Brongniart ; the operculum is seen at a. 
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Liey. 138. SPHERULITES FROM THE CHALK OF FRANCE AND ENGLAND. 
Fig. 1.—SPH#RULITE, with its operculum, a. 
2.—SpuH#RULITES Mortoni (G.A. M.), from Lewes: 3 nat. 
2a,—Cellular structure of fig. 2, in a transverse section: x 
26,—Structure, as seen in a vertical seciion: x 
The species found in the Sussex Chalk, Lign. 138, jig. 2, 
is characterized by the longitudinal striz on the outer 
surface. In some examples there is an external longitu- 
dinal furrow, and a corresponding internal ridge.* 
The Spherulites sometimes occur in groups in the Sussex 
chalk ; I had a large water-worn mass, consisting of five or 
six individuals, anchylosed together. Some beautiful speci- 
mens collected by the late Mr. Dixon from the Chalk, near 
Worthing, are now in the British Museum.f The structure 
of the Spherulite is accurately delineated in Lign. 138, 
* The specific name is in honour of Dr. George Morton, of Phila- 
delphia, author of the “Synopsis of the Cretaceous Group of the 
United States.” 
+ Petrifactions, p. 468. 
