viii ECHINODERMATA SYSTEMATIC REVIEW 311 



with root-like processes at its base, or with irregularly arranged cirri : its proximal 





FIG. 257. Metacrinus Murray! (after P. H. Carpenter). Most of the arms and the larger ];ait 

 of the stem broken off. p, Pinnulse ; ci, cirri : ng, node. 



ossicle usually enlarged. Upper Jurassic, Chalk. Tertiary, Recent. Ehizocrinus, 

 Bourguetiarimu. 



