ÔcSO I. IKEDA : 



to a (lotailod study. Tlio inctamor])1iosis of AclinotrocJia is, of 

 coiirso, one of tlio most curious phenomena in the animal ontogeny. 

 Rut the question whieli interested me almost to the same extent 

 was: how do the free swimmins; larvae come to estahlish colo- 

 nies at such fixed and limited spots as are found in the .Vhui-a- 

 tsuho inlet? Accordingly I made sevei-al visits to the Misaki 

 Station solely for the ])ur])Ose of ohtaining clues to the elucida- 

 tion of this point. The results obtained are, I think, worth 

 mentioning'. 



As I have before stated, the breeding season of PJioronis 

 iiiriiai ranges through about one half of the year, sav, from 

 November to dune or July, during which months the swimming 

 larvœ, thongh few in number, are constantly found in Abnratsubo. 

 They, are, however, most a1)andant from the middle of July 

 to the iniddle of August. Among these larvae some are very 

 young, having apparently just swum out of their birth-place ; l)ut 

 the majority of them are full}^ grown. 



On July 16th., 1808, I visited the place where Phoronis 

 ijlmai Honrishes, to see if it was still in possession of embryonal 

 masses. But these could no longer be found in the tentacular coils 

 of the mother animals whicli Avere, however, in the normal state. 



On the 22nd. of the same moiith, I went again to the same 

 place, and every thing was in the same condition as before. 



On August Gth. I visited the place for the third time and 

 to my astonishment I discovered that the animals had all died 

 off. Several deformed colonies were brought l)ack to the Lal)oratory 

 and we]-e kei)t in an cerated aquarium. On a close examination of 

 these colonies after a few hours, nearly all of the chitinous tubes 

 were found empty, only a few containing tlie jnitrefying remains 

 of the animal liodv. When I reexamined the colonies in the 



