42 



K. MITSUKUEI. 



papilla*, of Stichopus japonicus seem tod ecrease in number as well as 

 in height. This difference becomes so apparent when dried for the 

 market that dealers in dried " namako " divide them into those with spines 

 (papillae) and those without them. The former is the northern form, 

 while the latter from the southern part, show only a row of low papillae 

 along the lateral margins and few others scattered over the dorsal sur- 

 face. Those from Tokyo and the vicinity seem to be intermediate 

 between the two. I think that if the form found in the central part is 

 taken as the type of the species, the northern form with many papillae 

 might be distinguished as var. armatus, while the southern form with 

 few papillae might be called var. australis. Of course, these pass into one 

 another insensibly. And even at one and the same locality, there seems 

 to be a great deal of difference in different individuals in this respect. I 

 am inclined to think that the habitat of the animal has a great deal to 

 do with the matter. Those that live among rocks along a rocky beach 

 seem to be distinguished by a larger number of tall papillae as well as 

 by a mottled brown color, while those that live on sandy ground, 

 probably among sea-weeds, have lower and fewer papillae and have 

 generally a dark green color. So that it seems possible to me to divide 

 the species into varieties by latitude and by habitat. 



It would be a singular fact, if the changes in the shape of the calca- 

 reous deposits brought out above in Stickopus japonicus should turn out 

 tobe the solitary case of such an occurrence among the order of Holothu- 

 rioidea. I am rather inclined to think that if carefully studied, every 

 species will present more or less similar changes. If this should turn out 

 to be the case, I need hardly point out what an important bearing it has 

 on the systematic classification of the species of holothurioidea. At any 

 rate, those who collect holothurians should bear the fact in mind and 

 endeavor to obtain a large number of individuals in varios stages of 

 growth from different localities. 



Science College, Imp., Univ., Tokyo. 



Printed May 16, 1897. 



