XXX. N O T E vS ON SOME LEECHES IN THE 

 COLLECTION OF THE INDIAN MUSEUM. 



By ToKio Kaburaki, Research Student, Imperial University, 



Tokyo. 



(From llie Zoolotjical I.aboraUirx , the Museums, ( ambridge.) 



The present account is the result of the examination of a 

 large collection of leeches belonging to the Indian Museum, which 

 was placed by Dr. N. Annandale in mj- hands for identification. 

 The material was originally intended for use, in conjunction with 

 Mr. W. A. Hardingj in the preparation of a volume in the " Fauna 

 of British India " series on the said group ; but, as Mr. Harding is 

 unable to continue the work, it has become necessary for me to 

 take the whole responsiljility upon my,self, and also to confine my- 

 self to a rough investigation, owing to the unavoidable pressure of 

 many other studies during my stay in foreign countries. It is 

 hoped, therefore, that at least some of the species will be subjected 

 to full anatomical investigation in the future. 



Most workers on the systematic side complain of the enormous 

 difficulty of determining the species or even the genera of leeches 

 owing to the fact that the descriptions of many of the known 

 species are based solely upon e.\ternal characters without anj' regard 

 to internal structure. This seems to me to be more apparent than 

 real. It is, however, necessary, as has been mentioned by Oka 

 (1917), to submit the group to a thorough revision in reference to 

 internal characters. In the present paper, however, I have 

 adopted the generic designations in current use, leaving the prob- 

 lem to those who may have occasion to study personally a large 

 number of forms and especially to re-examine the species previous- 

 ly recorded. 



In the leech, as is well known, the large number of rings 

 found on the body resolve themselves into a series of regularly 

 recurring groups corresponding to the successive somites. It has 

 long been recognised that we have to account for twenty-seven 

 somites in the body excluding the posterior sucker, the number of 

 the somites corresponding with that of the ganglia in the central 

 nervous system. Towards the ends of tlie body the number of 

 rings in a somite becomes smaller, and at the extremities one or 

 more somites are found represented by only one ring. 



Much debate has arisen as to the determination of somite- 

 limits. In this communication, however, I have intentionally 

 abstained from taking part in such a discussion and have adopted 

 the neuromeric standard of somite-limits advocated bv Moore 



