52 



CANADIAN FOSSILS. 



Genus Cleiocrinus, Billings. 



(Clbioceinus, Report Geological Survey of Canada, 1856, page 2T6.) 



Fig. 17, 



Figure 17. Diagram of the structure of the cup in the genus Cleiocrinus. 



Generic characters. — Cup, large, conical or pyriform ; basal plates, 

 five ; rays, five, alternating with the basal plates ; the third plate of 

 each ray is pentagonal and bears two secondary rays, which are 

 several times divided above. Between two of the rays a single 

 vertical series of azygos inter-radial plates extends from the base to 

 the margin of the cup. The azygos plates and rays are all firmly 

 anchylosed together by their lateral margins up to the height of the 

 fifth or sixth sub-division. The column is pentagonal or nearly round. 



This genus has the structure of a Pentacrinus, with numerously 

 divided arms all soldered together in the walls of the cup. 



