1920.] 



Fauna of the Chilka Lake 



The male genital orifice lies in somite xi, 

 and the female orifice in somite xii. 



There are two pairs of eyes on the anterior 

 sucker, one pair on either side of the mid-dor- 

 sal line. The component eyes of each pair 

 are linear in form and inclined together at an 

 acute angle in such a way as to resemble the 

 equal sides of an isosceles triangle lying 

 horizontally, with its apex pointing towards 

 the margin of the sucker. 



The eyes in each pair do not actually 

 touch at the point of inclination ; they may 

 be somewhat curved outwardly or, again, so 

 closely approximated as to give, at first sight, 

 the appearance of one linear eye. 



Hosts, Habitat. 



This leech is a fish parasite and has been 

 recorded from Hypolophus sephen, Tetrodon 

 reticularis and Dorosoma indicum (Chatoessus 

 chacunda). It has so far only been found in 

 the Chilka Lake. The following examples 

 from this lake were examined : — 



(a) "Station 52. 4 mi. E.£N. of Patsa- 



hanipur. On Hypolophus sephen 

 (Forsk.) found crawling on lower 

 surface of body, in the gill-slits, 

 near the anus and within the mouth 

 on the palate. Sp. gravity of water 

 1-007 — I "Oil." 



(b) " Station 22. E. side of Rambha Bay, 



base of Ganta Sila. Sp. gravity of 

 water 1*007 — l'on. Found on a 

 man's foot after wading." 



(c) " Station 49. 4-9 mi. E. \ S. of Barkul 



bungalow." 

 id) "Station 85. Satpara. On Tetrodon 



reticularis (Bl.). Sp. gravity of 



water about 1-026." 

 (e) "Station 14. E. side of Rambha Bay. 



Sp. gravity of water 1-007 — l'on." 

 (/) "Station 55. 2-8 mi. N.B. \ E. of 



Kalidai." 



r iirudinea. 







eyes 



i-v<;'' r 



' '1 ^ 

 ^jty-^»brwwn bands 



VI -z;-- 





VII-:;" 



1 „ \ x 

 1 — — 1 n 



f — v — 1 v 



viii<;;'/ 



IX<^j 



^C^ ^>v>hite bands 

 ,SkA / and spots 



x<:'' I 



_r\ — y 



xi <:~'"fc 



-yH-...^ 



xn<;'' h 



-v=l— 9 



xm<;'' N- 



x 1/ 



.. JZ.h----p.ves.]. 



513 



XI V<' 



XV< 



XVI< 



XVII< 



XVIII<' 



XI X'. 



xx< 



xxi<. 



xxik^ 

 xxiiK' 



XXIV--' 

 XXV- 1; 



XXVI - 



XXVII" 



y\ 



V 



\ 



f\ 



\f 



\ 



IX 



J 



\J~^\ 



J 



) white bands 

 ■s 1 and spots 



\ 1 



-p. ves. 11. 



-an. 

 1 J^> white rays 



Fig. 1. — Piscicola olivacea, n. sp. Diagram 

 showing dorsal pattern, somites 

 (numbered in Roman figures,), eyes, 

 etc. 

 An, Anus ; p. ves. 1 and p. ves. 11, 

 Pulsating vesicles (shown only on 

 one side, for the sake of clearness) 

 of first and eleventh pairs. 



