28 ART. 9. 1. IJIMA : HEXACTINELLIDA. 



the case, the entire ray is in all essential points comparable to 

 that of a spiny microxyhexactin (PI., fig. ( J), such as we have 

 seen in Gorbitella speciosa or G. elegans. Sometimes a ray is seen 

 to end rather abruptly, apparently without being broken off at 

 the point, and to send out a spine close to that end at varying 

 angles. This leads over to cases in which a ray appears simply 

 bent at a certain distance from the outer end, and also to those 

 in which a ray, though nearly straight throughout, shows a sudden 

 diminishing in caliber at a similar position. I have therefore 

 been led to the belief that in certain cases — but not in all — the 

 terminal portion of a ray, much as it may took like a direct 

 elongation of the ray itself, is to be considered as a spine of 

 secondary nature and not as a part of the ray proper. This 

 would be much the same as the relation between a terminal and 

 a principal in a hexactinose hexaster. 



Further it very frequently happens that towards their outer 

 end the rays appear more as if split into two or three, sym- 

 metrically or asymmetrically divergent branches, rather than as 

 bearing one or two spines at the spot (see figs.). Nevertheless, 

 a close observation may sometimes reveal the fact that one of the 

 branches, owing to a slight difference in caliber or in the manner 

 of origin, may not improperly be interpreted as a part of the 

 ray proper and the rest as secondary appendages or spines. But 

 at other times all the fine branches are so exactly similar in 

 appearance that it is impossible to attempt the distinction. I am 

 greatly inclined to believe that in many, if not all, such cases what 

 appear as branches are really all spines borne at the extreme end 

 of a ray, similarly to the terminals in an oxyhexaster are. A 

 demonstration of the extent of the axial filament in the rays 

 should make the matter clear. However, by examining the spicules 



