1915-] Fauna of the Chilka Lake : Oligochaeta. 145 



E. barkudensis was found at only one spot in the Chilka Lake, namely in a 

 small patch of sand at one side of the landing-stage on Barkuda Id., in the main 

 area. It lives there, with Pontodrilus bermudensis f. ephippiger, some inches below 

 the surface and well below water-level. The months in which specimens were 

 obtained were July and November. In the former the specific gravity (corrected) of 

 the water immediately off Barkuda Id. was 1-015, while in November it was 1005. 

 The species was taken in January at the edge of the Ennur backwater near Madras, 

 also in wet sand and with P. bermudensis, the specific gravity of the water being 

 about 1-0025. O n all three occasions sexually mature worms were obtained. 



Family MEGASCOLECIDAE. 



Genus PONTODRILUS, E. Perrier. 



Pontodrilus bermudensis, Bedd., forma ephippiger (Rosa). 



1914. Pontodrilus ephippiger, Stephenson, Rec. Ind. Mus. X, p. 256. 



In life this worm has a bright pink colour. 



In the Chilka Lake specimens were obtained both in the main area and in the 

 outer channel at all times of the } r ear. They occurred at the extreme margin in wet 

 sand or sand mixed with mud, sometimes under stones with the amphibious Isopoda 

 Hemiporcellio carinatus and Arhina barkulensis, Collinge,' the water being either fresh, 

 brackish or as salt as that of the Bay of Bengal. Probably, however, the species 

 does not breed in fresh water, as no fully mature individuals were found in the 

 fresh- water season (July to September). The chief breeding- time seems to fall in late 

 winter and early spring, when the water of the lake varies in corrected specific 

 gravity from 1008 to 1-026. At the edge of the Ennur backwater near Madras the 

 same form was found in January, 1915, in sand wetted by water of specific gravity 

 of about 1-0025. Some of the specimens were mature. 



The species is very widely distributed on the warmer coasts of both hemispheres. 

 Following Michaelsen {Mitt, aus dem Naturh. Mus. Hamb., xxvii, 1909) I now 

 recognize P. ephippiger , Rosa, as one of the numerous forms of P. bermudensis , Bedd. 

 The form ephippiger is recorded from Christmas I., Celebes, and the Hawaiian Archi- 

 pelago; the form insularis of the same species (formerly P. insularis, Rosa) has been 

 found, among other places, in Ceylon. 



Family GLOSSOSCOLECIDAE. 

 Genus CRIODRILUS (Hoffmstr.). 

 Criodrilus lacuum, Hoffmstr. 

 1914. Criodrilus lacuum, Stephenson, Rec. Ind. Mus, X, p. 256. 



The identification of this worm is, as stated in the above paper, not absolutely 

 certain, since the specimens were not fully mature. 



The natural colour of this worm is tinged with a peculiar ochraceous shade. 



1 Rec. Ind. Mus. XI, pp. 145, 147, pis. vi, viii (1915)- 



