CLASS II CYSTOIDEA 183 
radiating from the mouth towards the arm bases. Ordovician (Vaginaten- 
kalk) ; Russia, Sweden, and England. S. pomum, Gyll. 
Glyptosphaerites, Mill. (Fig. 299). Differs from the preceding in having 
long, branching, ambulacral grooves, and a short, well-developed stem. 
Ordovician ; Russia and Sweden. 
Protocrinites, Eichw. (Fig. 300). Nearly hemispherical, non-pedunculate. 
Ambulacra grooves long and branching ; arms unknown. Ordovician ; Russia. 
Fungocystites, Barrande. Clavate. Ordovician (Etage D); Bohemia. 
Proteocystites, Barrande. Devonian (Etage F) ; Bohemia. 
Holocystites, Hall (Megacystites, Hall). Elongated, cylindrical, or sub- 
cylindrical ; short-stemmed or stemless; with subcentral mouth. Arms 
minute, springing from the ends of the ambulacral grooves. Silurian ; North 
America, Gottland. 
Eucystis, Angelin. Ordovician. Gomphocystis, Hall. Silurian. 
Family 3. Camarocystidae. Barrande. 
Calyx globose or discoid, composed of numerous polygonal plates, and sometimes 
fixed by the ventral surface. Interior of calyx divided into four to six compartments 
by partitions corresponding in position to lobes on the exterior. Stem long and slender. 
Silurian. 
This family embraces two genera whose systematic position is still doubt- 
ful. The larger, Camarocrinus, Hall (= Lobolithes, Barrande), occurs in the 
middle and upper members of the Silurian in North America and Bohemia, 
and attains considerable size. The smaller, Lichenocrinus, Hall, is more or less 
crateriform, has a very long, tapering stem, and is invariably attached by its 
flattened ventral surface. It is found in the Ordovician (Hudson River 
Group) of North America. 
Family 4. Echinosphaeritidae. Neumayr. 
Calyx globular or bursiform, adherent or with short stem, and composed of 
numerous, irregularly arranged plates, all of which are furnished with pore-rhombs. 
d 
il 
na 
lies 

Fic. 301. 
Echinosphaerites aurantium, Hising. sp. Ordovician (Vaginatenkalk) ; Pulkowa, Russia. a, Summit view of 
calyx; b, Calyx seen from the anal side; ce, Mouth, arms, and covered ambulacral grooves; d, Calyx plates 
enlarged, showing pore-rhombs (cf. Fig. 296). 
Ambulacral grooves short; arms two to five, free, biserial, rarely preserved. Stem, 
when present, composed of several vertical series of alternately arranged plates. 
Ordovician and Silurian. 
Echinosphaerites, Wahlenb. (Fig. 301). Globose, non-pedunculate. Mouth 
central, ambulacral grooves short. Anal opening protected by valvular 
