1915-] Fauna of the Chilka Lake : Echiuroidea. 61 



in dense mud. The largest of the three was brought up on the anchor of the launch 

 between Barkuda Id. and the mainland in April; the other two were taken out in 

 the lake between Barkuda and Chiriya Ids. in February ; the specific gravity of the 

 water varying from rooôon the former occasion to 1009 01 the latter. The species 

 is doubtless a permanent inhabitant of the southern part of the lake and must at 

 times be brought in contact with water that is almost fresh. The habits of the species 

 render it unlikely to be captured except occasionally, and we have no means of 

 ascertaining whether it is actually scarce. 



Our specimens of T. dendrorhynchus , the types of the species, are numbered 

 Z.E.V. 6800-6803/7 in the register of the Indian Museum collection. 



Thalassema branchiorhynchus, sp. nov. 



This species (fig. 2, p. 58) is closely related to T. dendrorhynchus, but differs in 

 the following characters : — 



(1) The proboscis is relatively longer and more slender, its length when fully 



expanded being more than one-third that of the body. 



(2) The dendritic outgrowths of its margin are much more highly developed, 



having a gill-like appearance (fig. 3) and being of a blood-red colour 

 in life ; they are confined to the proximal third of the margin, the distal 

 • part of which is quite smooth. 

 (3, There is a conspicuous longitudinal ridge (in place of the ordinary ciliated 

 groove) on the proximal part of the ventral surface of the proboscis be- 

 tween the two rows of dendritic outgrowths. These it resembles in colour. 



(4) The external (dorsal) surface of the proboscis is minutely tubercular instead 



of being smooth. 



(5) The integument of the body remains translucent even in spirit, the 



nerve cord being visible externally as an opaque white line. 



(6) The surface papillae of the body are less prominent than in T. dendrorhyn- 



chus; they are, as a rule, distinctly of two kinds, large and small, the 

 large papillae being most numerous towards the two extremities. Near 

 the posterior end they are conical and show some tendency to be 

 arranged in transverse rings. There is, however, no smooth circum-anal 

 region. 



The length of the body in the type-specimen (fully expanded) is about 32 mm. 

 and the greatest breadth about 7 mm. ; the length of the proboscis nearly 15 mm. 



In the living animal the whole body was of a deep reddish vinous tint, trans- 

 lucent, but not markedly so. The posterior extremity was somewhat paler than the 

 remainder and the colour seemed to be due mainly to the fluid of the body-cavity. 

 The proboscis was purplish pink, contrasting notably with the bright red colour of its 

 dendritic outgrowths and the ridge on the ventral surface. The hooks were golden 

 yellow tipped with black. 



The internal structure of this species agrees closely with that of T. dendrorhyn- 



