668 



Memoirs of the Indian Museum. 



[Voi,. V, 



nearly allied to the genus Platybdella Malm., but it is distinguishable from this by the 

 difference in the number of rings forming the complete somite as well as in some 

 structural respects. It is, I think, better to regard this leech as a member of Piscicola 

 occupying a position on the border between this genus and Platybdella. 



Pterobdella amara, n. g., n. sp. 1 

 (Figs. 3, 4.) 



Some remarkably interesting examples appearing to represent a new genus and 

 species were obtained near Kalidai and four miles E. | N. of Patsahanipur, from the 

 mouth of Hypolophus sephen as well as near Manikpatna, from the mouth of Trygon 

 uarnak. Usually they are to be found firmly adhering to the gums of their hosts.. 



This leech is of some resemblance in its features to Blanchard' s Piscicola elegans 1 

 described by that author from Kiu-Kiang and Yang-tse-Kiang in China. The body 



is depressed anteriorly and almost cylindrical posteriorly. As 

 is seen from Fig. 3, it presents a peculiar shape, being sharp- 

 ly divided into three distinct regions, each of which is on 

 some occasions about one-third the entire length of the body, 

 though the anterior region is usually shorter than the other. 

 The two anterior regions are each provided with a pair of 

 conspicuous lateral fin-like bodies, extending almost through- 

 out the length of each region, while the posterior region is 

 bare, without being marked with any trace of appendages. 

 The anterior sucker is somewhat excentrically attached, near- 

 ly campanulate and much smaller than the posterior sucker, 

 which is centrally attached and represents a thick circular disc, 

 as is the case with Pontobdella, Ichthyobdella and Ancyrobdella, 

 with the diameter about as broad as the posterior part of 

 the trunk. The specimens from Hypolophus are large, mea- 

 suring about 12 mm. long, inclusive of the suckers, by about 

 3 mm. across at the middle, while the examples from Trygon 

 are much smaller, being about 10 mm. in length and 2. mm. 

 in breadth. 



A correct count of rings forming the trunk is almost an 



impossibility. So far as I have examined the posterior region 



of the body where the rings are more or less distinct, the 



complete somite appears to be formed of some fourteen rings, which are merged 



into irregular groups. 



The ground colour is white, occasionally marked, according to Dr. Annandale's 



Fig. 3.— Pterobdella] 

 amara, n. g., n. sp. Dor- 

 sal aspect. 



1 Here I beg to express my indebtedness to Dr. H. A. Baylis of the British Museum for his sugges- 

 tion of the generic name " Pterobdella." 



Blanchard, R., 1896. Description de quelques Hirudinées asiatiques. Mèm. Soc. Zool. France, 

 T. TX. 



