182 ECHINODERMATA—PELMATOZOA SUB-KINGDOM III 
Family 1. Aristocystidae. Neumayr. 
Calyx composed of numerous heavy plates, arranged either irregularly or in  suc- 
cessive zones, and covered on both sides by a calcareous integument. Calyx plates 
traversed by simple canals terminating on either surface in pores distributed either singly 
or in pairs. Ambulacral grooves subtegminal (“ hydrophores palmées”) ; arms want- 
ing ; stem obsolete or very short. Ordovician. 
Aristocystites, Barr. (Fig. 298). Calyx bursiform or ovate ; ventral surface 
with four apertures. Ordovician (Etage D) ; Bohemia. 
Deutocystites, Barr. Ventral surface with three apertures. Craterina, Barr. 
Conical, truncate. Pyrocystites, Barr. Clavate in form. All three genera in 
Ordovician (Etage D) of Bohemia. 

Fic. 299. 
Glyptosphaerites Leuchtenbergi, Volborth. Ordovician; St. Petersburg. 
a, Calyx seen from above (natural size); b, Same from the dorsal face, with 
stem attached, reduced 1/y (after Volborth); c, Calyx plates showing double 
pores (enlarged). 

Fia. 298. 
Aristocystites Bohemicus, Barr. Fic. 300 
Ordovician (Dd4); Zahorzan, P i 
Bohemia. a, Side view; b, Sum- Protocrinites oviformis, Eichwald. Ordovician; Pulkowa, Russia. 
mit aspect (after Barrande). a, Calyx viewed from above ; b, Same from below (after Volborth). 
Family 2. Sphaeronitidae. Neumayr. 
Calyx globular or cylindrical, short-stemmed or stemless, and composed of numerous 
irregularly arranged plates with pores united in pairs. Ambulacral grooves either 
open or protected by covering plates, and either short and simple, or elongated and 
branching. Arms as a rule exceedingly small and primitive. Ordovician and 
Silurian. 
Sphaeronites, Hising. Globose, stemless. Five short ambulacral grooves 
