ORDER I ASTEROIDEA—EUASTERIAE 209 
occur with large, tuberculous plates on the abactinal area, which are often 
armed with powerful spines. Upper Jura to Recent. 
Sphaerites, Quenst. Under this title are included detached hexagonal 
mv A i ad 

Fic. 340. 
Metopaster Parkinsoni, Forbes sp. Lower Chalk; Sussex. A, Ventral aspect. 3B, Viewed from one side 
(after Forbes). 
plates of variable size and thickness, which are of not uncommon occurrence 
in the Jura of Wurtemberg and Switzerland. Some of them bear strong 

Sphaerites scutatus, Goldf. 
Upper Jura; Sontheim, 
Wurtemberg. 

rietGei Fia. 343. 
G. - 
; A, Sphaerites tabulatus, 
A, Pentaceros jwrassicus, Zitt. Upper Jura; Bemfeld, near Ingol- Goldf. B, S. punctatus, 
stadt, Bavaria. 1/5. B, P. thoracifer, Gein. Planer; Plauen, Saxony. Goldf. Upper Jura; Streit- 
Marginal plate. C, P. primaevus, Zitt. Upper Jura; Streitberg. berg, Franconia, 
conical spines (Fig. 342), and others are smooth or punctate (Fig. 343). 
Their zoological position has not as yet been satisfactorily determined. 
VOL. I 1 
