276 



CPJNOIDEA. 



In the family of the AntJwcrinidce we have only the extra- 

 ordinary Silurian genera which have been described as AntJio- 

 crinus and Crotcdocrinus. In the former of these (fig. 163), 



Fig. 163. A, Calyx and arms of Anthocrinus Loveni, cut across to show how the arms arc 

 rolled up ; B, A portion of the network formed by the arms, enlarged. Upper Silurian. 

 (After J. MUller.) 



which is the best known, the calyx consists of five basals, 

 five parabasals, and a single zone of radials, while inter- 

 radials are wanting, and there is only one anal plate. The 

 arms are bifurcated, and the subdivisions unite with one 

 another by means of lateral processes, thus giving rise to 

 a network, perforated by numerous apertures (fig. 163, B). 

 The five flattened or leaf-like expansions, produced by this 

 curious metamorphosis of the arms, are rolled up like the 

 petals of a flower. Crotalocrinus in the conformation of its 

 arms appears to resemble Anthocrinus, except that the edges 

 of the arms appear to be united, but the structure of the 

 calyx is somewhat different. 



Fig. 164. Haplocrimis mespiliformis. The calyx viewed from below, from one side, 

 and from above. Devonian. 



Lastly, we must place here the little family of the Haplo- 

 crinidce. In the Devonian genus Haplocrinus (fig. 164) the 

 calyx is small and globular, with five small basals, sue- 



