58 Art. 2. — T. Kabiiraki ; 



become sexually mature when the temperature comes the nearest 

 to their ancestral condition. The other is that eggs which are able 

 to develop slowl>^ or lie dormant for some time, if deposited in the 

 fall, will be ready to begin a more rapid growth in the spring 



Budding. — That heteromorphosis can be produced experimen- 

 tally in the planarian has been proved by a number of investigators 

 (see Steinmaxx (72)). In nature there also occur various hetero- 

 morphic forms with double or more head or tail portions, upon 

 which little has hitherto been observed. During my work I have 

 met with such on several occasions in S. Sapporo, PI. vivida and 

 PL (jonocephala, as previously noted (43). Among these a very 

 curious case was obtained in a specimen of S. Sapporo in which the 

 mother-individual bears on the left lateral margin of the body in 

 the phar3mgeal region two branch-like buds of considerable size. 

 One of them represents an additional posterior part of the body, 

 and the other an additional anterior part of the body, the latter 

 lying between the former and the posterior part of the mother- 

 individual. The small daughter-individual with the end of the 

 head directed posteriorly in I'elation to the mother-individual 

 crawded forwards, though at times it made efïorts of forward crawl- 

 ing in its own sense. As mentioned by van Duyxe (23), each 

 piece would move away from the other until they had completely 

 torn apai t. 



On the Parallelism in the Distribution of Freshwater Planarians 



in Europe and Japan with a Consideration of the Causes 



underlying this Distribution in the two Regions. 



\\'lietber Japan ever underwent a glacial age is the subject of 

 much controversy among geologists. Most interest attaches to the 

 conßicting views of Yokoyama and Yabe. From the palaeontologi- 

 cal point uf view, Yokoyama'' puts forward the view that the 

 climate of Central Japan eUning the Pliocene epoch was on the 



(1) YtKOVAMA, M., 1911. Cliuiatio Chaugt^s iu .Japan since the Pliocene Epoch. Jonrn. 

 Coll. of Sei. Imp. Univ. Tokyo, Vol. XXXII, Art. 5. 



