CTENOPHORA. 



By N. AnnandaIvE and Stanley Kemp. 



The only member of this group represented in our collection is a representative 

 of the order Cydippidea and of the genus Pleurobrachia , Flemming, forming a race of 

 P. globosa, Moser, a species originally described from the Malay Archipelago. For 

 this race we propose the name bengalensis, as it occurs on at least one side of the Bay 

 of Bengal and differs from the form found in the Gulf of Manaar to which Browne ' 

 has given the name ceylonensis. 



Pleurobrachia globosa bengalensis must be classed as a periodic visitor to the 

 Chilka Lake, over the whole of which it is found for a great part of the year. In the 

 fresh- water season, however, it disappears, and does not re-appear until the water 

 has regained a certain salinity. From observations made in the Ennur backwater, 

 near Madras, in January, 1915 it would seem that it is able to live in a medium of 

 sp. gr. 1*0045, but not in one of 1/0025. 



In the outer channel of the lake, in the salt-water season of 1914, we captured 

 in our tow-nets on several occasions a species of the order Lobata but the animal 

 was so fragile that we failed to preserve specimens. In formalin it seemed literally 

 to melt away and all attempts at narcotizing it had the same effect. 



Pleurobrachia globosa, Moser. 



1903. Pleurobrachia globosa, Moser, Siboga-Exp., XII (Ctenophora), p. 7, pi. i, figs. 1-4. 



The typical form of this species has not been found in the Indian Ocean. We 

 have already alluded to the race endemic in the Gulf of Manaar. 



Race bengalensis, nov. 



(Plate ix, fig. 5.) 



In all the more important structural features {viz. the relative position of the 

 tentacle-sheaths, of the tentacle openings, the canals and the stomodaeum and the 

 proportions of the tentacle-sheaths) this race agrees with the typical form of the 

 species, from which it differs in all the points noted by Browne in his description of 

 his variety ceylonensis. From that form, however, it differs in that in the vast 

 majority of individuals, the costae are still longer, being about twice as long as in the 

 typical form and at least a quarter longer than in ceylonensis. The length of the 

 meridional canals, which extend for the whole length of the costae, is also relatively 

 longer than in the latter, but the opening into them of the adradial canals is also 



Herdman's Ceylon Pearl Fisheries IV, p. 161 (1905). 



