GEODIA AGASSIZII. 



137 



The large oxysphaerasters of the specimens from Station 4228 above re- 

 ferred to, which in their dimensions equal the sterrasters, are rather similar to 

 some of the young stages of the sterroids. They may therefore be such spic- 

 ules, in which the development has, as it were, gone wrong, the thickening of 

 the rays, which normally leads to the formation of a large soUd centrum, and 

 the formation of the spines on the rays having been suppressed. 



LOCALITIES AND NATURE OF ENVIRONMENT. 



The young stages of the sterroids have been observed only in the young 

 specimen from Station 4228 and in the immature specimen described by 



