88 Memoirs of the Indian Museum. [Vol. V, 



body-wall in specimens in which the circular muscles are contracted or relaxed has 

 already been noted (p. 78) ; in Pelocoetes it is even more marked. When the column is 

 fully expanded the total thickness of the wall is reduced to about 002 mm. and the 

 mesogloea is a mere thread even under high powers, whereas in examples killed with 

 these muscles contracted the wall is about 0-17 mm. thick and the mesogloea, includ- 

 ing the muscle-band, 0^028 mm. thick. 



If the muscles are at all contracted there is always a tendency for the column of 

 P. exul to assume an oval form in cross-section and this feature may be observed 

 to some extent even in the living animal; the main axis of the section is sulco- 

 sulcular (fig. 5, p. 87). 



The types of the species, which are from Port Canning, are numbered Z.E.V. 

 241 9-21/7 in the books of the Indian Museum. 



P. exul has been found only in small pools of brackish water at Port Can- 

 ning in the Gangetic delta and in the main area of the Chilka Lake, but its habits 

 render it very 'difficult of detection and capture and it is actually, in all probability, 

 distributed more widely than we know. In the lake it was taken close inshore at 

 Rambha in a few inches of water in January and off Kalupara Ghat in the northern 

 part of the area in very shallow water in April. The salinity of the water is not 

 precisely known, but the specific gravity must have been between 1*005 an d i"Oio. 



This anemone lives, as already stated, buried in the mud up to the base of its 

 oral disk, which can be pulled downwards with great rapidity on disturbance. It 

 is nocturnal in habits to this extent — the tentacles are never fully expanded by day 

 and remain with their tips extending from the hole in the mud for a short distance 

 only, whereas by night they are completely extended. These facts were observed 

 in the case of anemones in situ at the edge of the lake in January. A bright light 

 directed on the disk, however, did not cause contraction. Although in early life 

 the animal must be an active burrower as it lives in a vertical burrow several inches 

 deep, adults are very helpless when removed from their proper environment and 

 show no inclination to make a fresh hole. Their vermiform column prevents them 

 from assuming an upright position, and it is very difficult to keep them alive in 

 captivity unless they are literally planted in mud in the way described in the footnote 

 on p. 86. Further particulars as to the habits of P. exul will be found in my paper 

 of 1907. 



In specimens taken in the Chilka Lake in January the ovaries were mature ; 

 this was also the case with specimens taken at Port Canning in December ; but in 

 others taken at the latter locality in January it was the testes that were ripe. 



Family EDWARDSIIDAE. 



1905. Edwardsiidae, McMurrich, Zool. Jahrb., Suppl. VI (III), p. 218. 



Remarkably few species of this family have been found in the warmer seas and 

 the occurrence of two genera, representing respectively the Edwardsia and the Hal- 

 camp a sections of the family, in a locality so peculiar as the Chilka Lake is therefore 

 noteworthy. • 



