ü88 T. IKEDA : 



the Ibriner liguro corrosjiond respect ivcly to the dorsal vessel and 

 the trunk cavity (anterior j^ortion) in the latter. Again, in re- 

 gard to the alimentary canal, Roule states that the end portion 

 of the intestine atrophies, but according to the observations of 

 Caldwell and myself, no portion of the larval alimentary canal, 

 except the stomach diverticulum, undergoes histolysis during 

 metamorphosis, the entire tract growing gradually in length. 



Roule's views as to the origin of the blood vessels greatly 

 differ from those of Caldwell, Masterman and myself. Accord- 

 ing to KouLE, the vascular spaces and the Ijody -cavities are on- 

 togenetically the same thing, and the former is formed from a 

 coalescence of the irregular lacunal sj)aces of the latter. Tliough I 

 agree with him in considering the ring vessel of the adult as a 

 dei'ivative of the l)ody-cavity (collar) of ActinotrocJia, yet I can 

 not acce])t his view attributing other vessels to tlie same process. 

 Besides, we see in his figures (82, 83, 8(;, 87, 88, etc.) tliat the 

 same vessel (dorsal) is placed sometimes l>etween the afferent, and 

 the efterent, l)ranches of the intestine, and sometimes on the somatic 

 walls. Can such a peculiar disposition of the blood vessels against 

 the skin l)e verified in the adult animal ? 



It may ]ie known from Roule's c()ntril)utions, that the larval 

 development is more accelerated in P. sabatieri than in other 

 species. So that the ventral ])Ouch and some other organs are in 

 that species already well developed even in a lai'va of (3 tentacles. 

 But this seems of not much significance, since we know that even 

 in the same type of the larv?e the j^'ogress of larval organisation 

 does not always keep pace with the increase in the numbei" of the 

 tentacles. 



