1921.] Fauna of the Chilka Lake : Leeches. 671 



The female organs consist of the usual pair of small ovarian sacs which com- 

 municate by a short narrow duct with the vestibulum. 



This remarkable leech is nearly allied, as is evident from the above, to Piscicola 

 elegans from China, but a closer examination has revealed the fact that it cannot be 

 ranged under the genus Piscicola, as dealt by Blanchard with elegans. To my mind, 

 a minute investigation of the latter species would necessarily result in its generic dis- 

 tinction from Piscicola. This leech is also closely allied to the genus Trachelobdella 

 Diesing, but stands distinctly at variance from this in the general shape of the body* 

 not to speak of other points of differences. 



The following are the chief characters which distinguish this new genus Pterob- 

 della founded on a single species. 



Brackish water leeches, ectoparasitic on fish. Body smooth, formed of three 

 distinct regions, of which the anterior two are flattened and each provided with a 

 pair of lateral fin-like bodies ; but the posterior region is cylindrical, without pulsat- 

 ing vesicles. Anterior sucker nearly campanulate, excentrically attached; posterioi 

 sucker circular, disc-like, centrally attached. Without eyes. Complete somite, 

 though still uncertain, may be said to consist of some fourteen rings which are 

 merged into irregular groups. Crop produced into five pairs of pouches, without 

 posterior blind sac. Male and female genital organs opening in common. Testes 

 five paired. 



Glossosiphonia ceylanica, Harding. 



(Fig. 50 



The material was collected by Dr. Annandale and also by Dr. F. H. Gravely 

 „from the pond in the island of Barkuda. This leech was found occasionally at- 

 tached to the body of Rana cyanophlyctis. At a glance some examples appeared 

 to be identical with G. heteroclita, but a closer examination has revealed the fact 

 that this is not so. After some hesitation I have referred it to Harding's G. ceyla- 

 nica, 1 which has not been adequately described. This species appears to be fairly 

 common in India, some examples being found in the general collection. 



The body is nearly ovate-elliptical in contraction, and in some preserved speci- 

 mens the head is seen separated from the trunk by a slight neck-like narrowing. 

 No trace of papillae have I been able to demonstrate in the specimens examined. 

 The anterior sucker lies on the ventral side of the head, within the limits of rings 1-6. 

 The mouth occupies a position slightly anterior to the centre of the sucker. The 

 posterior sucker is somewhat ventral in position and oval or circular in shape, the 

 diameter measuring about 1 mm. The specimens measure about 8 mm. long by 

 2 mm. across at the middle of the body. 



On the dorsal side seventy-one rings are counted in front of the posterior sucker. 

 They are grouped into twenty-seven somites, of which somites I, XXVI and XXVII 



1 Harding, W. A., 1909. Note on two new Leeches from Ceylon. Proc. Camb. Phil. Soc. 

 Vol. XV, Pt. III. 



