1921.] Fauna of the Chilka Lake : Leeches. 667 



mouth is situated at about the middle of the anterior sucker, leading dorsally into 

 the pharyngeal sheath which continues backwards through the cephalic ganglionic 

 mass, extending into somite VIII. Within the sheath lies the pharynx which is of a 

 short cylindrical shape and is supplied at the base with numerous ducts of the sali- 

 vary glands. These glands are always unicellular and represent large and round 

 cells, which are extensively distributed in the anterior parts of the body. Posterior- 

 ly the pharynx is continuous with the crop filled with blood. The crop represents a 

 distensible part of the digestive tract, extending over ten somites XIII-XXII, 

 without being divided into two branches, and giving off ten pairs of sub-divided 

 lateral pouches which come off metamerically in these somites. Near the end of 

 somite XVIII the crop gives rise dorsally to the stomach which bears four pairs of 

 lateral pouches, a pair in each of somites XIX-XXII. The intestine extends through 

 five somites, being distinguished by a slightly winding proximal part and a simple 

 wide distal part, opening dorsally at the anus just between somites XXVI and XXVII. 



The coelome, though resembling that of the preceding species, is considerably 

 reduced, and no trace of lateral pulsating vesicles could be detected even in sections. 



Of the nephridia I have been unable to obtain any more insight than a few 

 ducts in sections available. 



The nervous system is very closely similar in its arrangement to that observed in 

 P. olivacea, there being twenty-one ganglia in the ventral chain, not counting the 

 cephalic and acetabular ganglionic masses. Bach ganglion occupies a position in the 

 middle of the corresponding somite. The cephalic ganglionic mass is, as usual, com- 

 posed of six ganglia, chiefly situated in somite VI ; the acetabular mass is made up of 

 seven ganglia. 



The male genital aperture lies in somite XI, as it seems to me, between rings 79 

 and 80, leading into the tubular vestibulum. The female aperture is situated fourteen 

 rings behind the male, in somite XII, being much smaller than the latter. 



The six pairs of testes exist anterior to and partly below the first six pairs of 



the crop -pouches, appearing to lie intermetamerically in somites -^-^^ . The 



XIII XVIII 



testes on each side are connected by short vasa efferentia with the vas deferens which 

 runs forwards and, after pursuing a somewhat tortuous course and dilating into a 

 thick-walled glandular canal in somites XI and XII, opens in common with its fellow 

 into the vestibulum as in the preceding species. Around the prostate is a large accu- 

 mulation of glandular cells which make their way into its lumen. 



The ovaries represent a pair of simple sacs lying in somite XIII, usually lateral 

 to the ventral nerve chain. Before opening to the exterior they unite into a short 

 common duct. 



In the specimens examined there can be also observed, as in P. olivacea, a swell- 

 ing of the body- wall, which occupies ventrally about one somite (XIII). 



- In spite of the entire absence of eyes and the reduction of the coelomic cavity 

 this leech may be placed in the genus Piscicola Malm., on account of its great 

 resemblance in external and internal features, as is evident from above. It is also 



