ORDER II CRINOIDEA—CAMERATA 143 
plates heavy, and more or less turgid. Anal tube nearly central, very long, and 
gradually tapering. Arms simple, biserial, and very short. Confined to the 
Sub-Carboniferous of North America. Type—B. icosidactylus, Cassed. 
Eretmocrinus, Lyon and Cassed. Like the preceding, but the J? of the 
dorsal cup continuous with those of the tegmen, and arms nearly twice as long ; 
their upper portions much wider, spatulate, and folded inward. Anal tube 
shorter than in batocrinus, and often bent abruptly to one side. Sub-Carboni- 
ferous ; North America. 
Dorycrinus, Roem. (Fig. 245). Calyx broadly turbinate or sub-globose, 
truncate at the base, and deeply sinuate in all the interradial areas, but chiefly 
so in the posterior one. Plates of the dorsal cup smooth or corrugated, but not 
striated, and all more or less convex. Tegmen strongly convex, composed of 
moderately heavy plates. Orals five, large; the posterior one nodose, or more 
frequently extended into a long spine, and occupying a central position. 
Surrounding these and overlying the ambulacra are five other spinous or nodose 
plates, which are separated by interradial pieces. Anus lateral in position, and 

Fic. 245. 
ees 
Dorycrinus quinquelobus, Hall, var. Fic. 246. 
intermedius, M. and W. Sub-Carbon- «, Habrocrinus comtus, Ang. Silurian ; Gottland. 
iferous ; Burlington, Iowa. Calyx Tegimen viewed from the anal side. Natural size; 
viewed from the anal side. Natural b, H. ornatus, Ang. Tegmen showing covering 
- size (after Meek and Worthen). pieces of the ambulacra (after Angelin). 
not extended into a tube. Arm openings twelve to twenty ; the arm-bearing 
plates protuberant. Devonian; Eifel. Lower Sub-Carboniferous; North 
America. 
Agaricocrinus, Troost (Fig. 231). Calyx much depressed ; basal disk flat or 
slightly concave. 2 supporting two primary br, which are followed by short 
distichals, and in rays with more than two arms, by still shorter palmars. J? 
of the dorsal cup rarely more than four ; those of the tegmen numerous, especially 
at-the anal side. Tegmen high, pyramidal; the upper end occupied by a 
massive, button-shaped, central piece, which is surrounded by four similar, but 
slightly smaller plates ; these constituting together the orals. Confined to the 
Sub-Carboniferous of North America. 4. Americanus, Roem. sp. ; A. pentagons, 
Hall. 
Alloprosalocrinus, Lyon and Cass. Warsaw Limestone. 
Habrocrinus, Ang. (Pionocrinus, Ang. ; Carpocrinus, Mill.), (Fig. 246). 2 three, 
equal. Costals 2 x 5; the distichals supporting the arms. Jd very large, 
aud followed by numerous //, arranged in rows of two or three plates. Arms 
aniserial, long, heavy, and simple throughout. Silurian ; Gottland and England. 
