34 



K. MITSUKURJ. 



forateci plates as " Hemmungsbildungen, " but von Marenzeli.er 

 makes no mention of them. As to what the shape of the complete 

 tables is, one will be sorely puzzled to find out. The figures and de- 

 scriptions given by Selenka and by Lampe rt will be found difficult to 

 reconcile with those of von Marenzeller or of Théel. Moreover, 

 while it seems certain that there are forms closely related to Stichopus 

 japonicus, such, for instance, as that described by Théel as var. typicus, 

 or that called by Selenka Holothuria(ov Stichopus according to Théel) 

 annata, it is impossible to know exactly in what relation these forms 

 stand to the species proper or to one another. 



When I began to examine the specimens of what 1 supposed to be 

 Stichopus japonicus my perplexity was greatly increased. For actual 

 specimens seemed to be about as varied as the descriptions of the above 

 mentioned authors. Individual after individual were found with only 

 perforated plates * and without any complete tables. Or if I succeeded 

 in finding some with complete tables, these latter seemed to show a 

 great variety of forms among themselves, so that it was impossible to 

 specify a shape common to all specimens. Finally, the question seem- 

 ed to resolve itself into this : Either there are two distinct species among 

 the form known in Japan as the common " namako " (hitherto supposed 

 to be identical with St ich opus japonicus), one species corresponding to 

 Holothuria armata of Selenka and the other to Stichopus japonicus of 

 the same author, or else the species known as Stichopus japonicus, 

 Selenka, presents an extraordinary variety of forms in their calcareous 

 deposits. If the former alternative was the case, it was most desirable 

 to establish the fact and to define the limits of each species, for it had a 

 most practical bearing on the question which it had been, and is, my 

 purpose to study, viz. how to protect or cultivate the namako for 

 economic purposes. If the latter alternative was the case, it would be 

 of great morphological interest to find out with what conditions, these 

 variations of the calcareous deposits are correlated. To settle the ques- 



* Apart from the terminal disc and supporting bodies of the tube-feet and papillse. 

 Of these, I am not at all speaking in the present article. 



