On Changes which are found with Advancing 

 Age in the Calcareous Deposits of 

 Stichopus japonicus, Selenka. 



By K. Milsukuri, Ph. D. 



Professor of Zoology, Imp. Univ., Tokyo. 



I am at present engaged in a study of the Holothurioidea of Japan, 

 the results of which I hope to publish elsewhere before long. But the 

 following facts in regard to the calcareous bodies of our commonest 

 holothurian —Stichopus japonicus, Selenka, — appear to me remarkable 

 enough to deserve a separate preliminary notice. 



The statements made by previous writers about the calcareous 

 bodies of that species do not in many respects agree with one another, 

 and it will be found difficult to obtain from them a clear idea on the 

 matter. This is not to be wondered at, as some most important facts 

 have hitherto been entirely overlooked. 



Selenka who gave the first description of the species (Zeitsch. für 

 wiss. Zool., Bd. XVII, p. 318) had only one specimen 110 mm. long. In 



34 



Fig. 1 



35 



36 



regard to the calcareous bodies, he says ; 

 " Die Kalkgebilde bestehen ausschliesslicli 

 in O.Oonwi. breiten thurmförmiyen Korper 

 (Fig. 34-35), unter denen ich sehr zahlreiche 

 Hemmungsbildungen, nämlich durchbroch- 

 ene Binge, finde (Fig. 36). " 



Von Maren zeller who next touched 

 on the subject (" Neue Holothurien von Japan und China, " Verbandl. 

 zoolog-bot. Gesellsch. Wien, 1881, p. 137) had several specimens, . the 

 largest of which was 70 mm. long and not sexually ripe. He says :— 

 " Die Kalkkörper sind, wie Selenka angiebt, von den Kalkstäben der 



Calcareous bodies of 

 Stichopus japonicus. Copied 

 from Selenka. 



