690 Records of the Indiiui Museiii/i. [Vol. XXII, 



(1900), Castle (1906) and some others. The sensory ring maj^ be 

 regarded as corresponding to the middle ring of each t3'pical so- 

 mite, lodging a ganglionic mass of the ventral chain and in several 

 cases possessing the " metameric sensillae,'' which are often 

 rendered conspicuous by association with special colour markings 

 and by elevation upon more or less prominent papillae. Of course 

 it is sometimes extremely difficult or nearly impossible to deter- 

 mine the somites by this means, because of the indistinctness or 

 the entire absence of papillae and colour markings. Here, how- 

 ever, I insist upon this conception : the Chinese species My- 

 xobdella annandalei , Oka (1917), seems to indicate that the neuro- 

 meric standard of somite-limits is true. In this .species the 

 body, though wholly devoid of segmental papillae, is divided by 

 deep furrows into distinctly bounded somites, each being subdivid- 

 ed into rings by much shallower ones. The ganglionic mass oc- 

 cupies a position in the middle of each typical somite. 



Here I deem it my duty to express my best thanks to Dr. N. 

 Annandale for the privilege of allowing me to examine this large 

 collection of leeches, and to Professor J. S. Gardiner for providing 

 me with accommodation in his laboratorj'. My thanks are also due 

 to Mr. W. A. Harding for giving and lending me some literature. 



The following is a list of the species dealt with in the present 

 paper : — 



Sub-order Rhynchobdellae. 



Family ICHTHYOBDEIXIDAE. 



1. Ozuhranchus jantseanus , Oka. 



2. Ozohranchus papiUaius , sp. nov. 



3. Ptcrobddla aniara, Kaburaki. 



4. Cystobranchus anoculatits, sp nov. 



5. Piscicola olivacca ^ Harding. 



6. Piscicola caeca, Kaburaki. 



Family GI.OSSOSIPHONIDAE. 



/ 



Heiniclepsis marginata (O. F. Miiller). 



8. Glossosiphonia ii'eberi, K. Blanchard. 



9. Glossosiphonia lata, Oka. 



10. Glossosiphonia ccylnnica, Harding. 



11. Glossosiphonia reticulata, s\t. nov. 

 12 Placobdclla emydac, Hardini:. 



Ij. '•' Placobdclla gracilis (R Blanchard). 



Sub-order .Vkhynchobdellae. 

 Family HKRPOBDELLIDAE. 



14. Hcrpobdella lineata (O. F Miiller). 



15. Herpobdella hexociilata , sp. nov. 



16. Hcrpobdelloidea lateroctdata , gen. et sp. nov. 



