OUDKIt If 



CR1NOIDEA CAMERATA 



143 



plates heavv, and more or less turbid. Anal tube nearly central, very long, and 

 gradually tapering. Anns simple, hiserial, and very short. Confined to the 

 Sub-Carbonifflroufl of North America. Type B. icosidactylus, Gassed. 



Erehnocrinuttf Lvon and Cassed. Like the preceding, but the Hi of the 

 dorsal dip (.minimus \\ith tho-e .f tin- teamen, and arms nearly twice as long: 

 their upper portions much wider, spatulate, and folded inward. Anal tube 

 shorter than in /A/Awy/'// */.-, and <.ften Kent abruptly to one side. Sub-Carboni- 

 ferous; North America. 



/A//-//OV////S, Uoem. ( Fi-. L'45). Calyx broadly turbinate or sub-globose, 

 truncate at the base, and deeply -innate in all the interradial areas, but chiefly 

 so in the posterior one. Hates of the dorsal cup smooth or corrugated, but not 

 Mriated, 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 



FIG. 24."). 



1/1/1 inii/i'/nhiix, Hall, VHI'. 



InterSMdlu*. M.and W. Sub-Carbon- 

 iferous ; Burlington, Iowa. Calyx 

 viewed from tin- anal side. Natural 

 sizt- (after Mrrk ami Wortlien). 



FIG. -240. 



a, IIal>i'<H-i-!iiiix <<>!, tt us. Aug. .Silurian ; (iottland. 

 Tegmen viewed from the anal side. Natural size ; 

 I, H. ortHitus, Aug. Tegmen showing cnveriii" 

 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. 11 supporting two primary r, which are followed by short 

 distichals, and in rays with more than two arms, by still shorter palmars. lit 

 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-Carboniferoua of North America. A. Americanus. Eoem. sp. ; A. pentuqonu* 

 Hall. 



Alhproaalocrinia, Lyon and Cass. Warsaw Limestone. 



Habrocrinus, Ang. (Pionocrinus, Aug. ; Carpocrinus, Mull.), (Fig. 246). JJ three, 

 equal. Costals 2x5; the distichals supporting the arms. IRA very large, 

 and followed by numerous IE, arranged in rows of two or three plates. Arms 

 uniserial, long, heavy, and simple throughout. Silurian ; Gottland and England. 



