HABITS AND LIFE-HISTORY OF ST.ICHOPUS JAPONICUS. 



but are absorbed gradually, and this view is confirmed by TheEL's 

 observations above referred to. 



I tried artificial fertilization several times but always without 

 success. The reason of this failure is no doubt as follows : although 

 eggs and spermatozoa are constantly arriving at maturity and being 

 shed, they do not attain this state en masse and therefore when a 

 mixture of the two elements is made, by far the largest part of the 

 elements are unripe and decomposition soon sets in. Only once I have 

 seen an egg divide to the eight-cell stage. 



In order to see the shedding of the reproductive elements, I kept 

 in a part of the bay at Kanagawa a large number of individuals in a 

 large box through which the sea-water freely passed, but I did not 

 succeed in getting any eggs that have been shed. I am however inclined 

 to think that spawning in this species takes place very much as in other 

 holothuriaus. That is, a number of individuals being in more or less 

 proximity males probably shoot forth the spermatic fluid and females 

 influenced in some way by it begin to shed eggs. This also probably 

 takes place at night, or toward dusk. 



Owing to my failures in obtaining either artificially or naturally 

 fertilized ova of this species, I am unable to give any facts on the 

 development of the egg or to identify the free-swimming larva belong- 

 ing to this species. 



The youngest specimens Of SticJiopus japonicus which I have 

 obtained were collected at Misaki. They were found attached to the 

 roots of alga: or gorgonians growing on rocks. The first one was dis- 

 covered by Mr. Mivajima on July 17, 1897. By searching for the 

 specimens on several following days several more were discovered. On 

 July 29, I with about ten of my comrades spent several hours on the 

 rocks exposed by low-tide and succeeded in collecting some more. 



Their sizes were as follows : 



