r. etheridge, jiin., on asteocrinites. 115 



Discussion. 



Prof. Morris complimented the author upon the care and labour 

 he had bestowed in working out this genus from the fragmentary 

 and minute specimens at his disposal. In the genera of Blastoidea, 

 to which this form belongs, the plates of the calyx vary in number 

 and form, as do also the orifices of the upper surface, in addition to 

 which the normal number of the pseudambulacra appears to be 

 only four, whilst in the other Blastoidea there are usually five. Oc- 

 casionally, however, some Echinodermata present the abnormal con- 

 dition of having only four rays. Besides the character of the rays, 

 the genus is further distinguished by being stemless, in which cha- 

 racter Astrocrinites, if rightly interpreted, bears the same relation to 

 the stalked Blastoidea that Marsupites does to the Crinoidea. 



