igi5-J Fauna of the Chilka Lake : Echiuroidea. 59 



The proboscis, the length of which is thus about one-sixth or one-seventh that of 

 the entire animal, is shovel-shaped ; the distal extremity is truncate and the lateral 

 (ventral) margins are capable of being applied together in such a way as to form 

 a cylindrical tube. When separated the space between them is narrowly V-shaped. 

 The dorsal surface is smooth or nearly so. There is no longitudinal ridge on the 

 ventral surface and the ciliated groove is inconspicuous. A striking feature of the 

 margins is that they are distinctly serrated , the serrations towards the proximal end 

 gradually taking the form of dendritic outgrowths, which, however, are always shorter 

 than half the width of the whole organ (fig. la). 



In certain conditions of expansion the basal part of the proboscis has the ap- 

 pearance of being annulated and the distal extremity is marked by short parallel 

 longitudinal grooves. 



The body is covered with papillae which are most numerous towards the two 

 extremities, where they tend to be arranged in concentric rings emphasized by corres- 

 ponding circular folds in the integument. This is more marked in the posterior region, 

 where the papillae are also larger, than in the anterior. There is a considerable area 

 in the posterior half of the body where they are scattered and comparatively small. 

 The ventral hooks are of a bright golden colour , but in two of our specimens the tips 

 appear to have been broken off. Even when complete they are small and only 

 conspicuous on account of their colour. They are situated close together and their 

 distance from the base of the proboscis is - considerably shorter than its length. 

 The exact point at which they occur is not, however, constant. 



The circum-anal region is devoid of papillae, but surrounded in a more or less 

 definite manner by several concentric folds, the most conspicuous of which separates 

 it from the densely papillate region immediately in front. As a whole it is conical, 

 but the part actually bordering the anus can be thrust out to form a short tubular 

 process. 



The longitudinal muscles form a continuous sheath. 



There are two pairs of nephridia, both of which open behind the level of the 

 ventral hooks. The internal funnel of each is provided with a pair of very long, 

 fine, spirally- twisted filaments which arise at either side of its orifice. The vesicle 

 is narrow and finger-shaped, tapering to a blunt apex which points inwards. 



The anal trees are short and simple, nearly half the length of the body in a 

 contracted specimen. They have a slight brownish tinge and the walls are very 

 thin ; the distal part is narrowly cylindrical, but the apex is blunt ; the basal or 

 proximal part is somewhat swollen, but there is no definite vesicle. No funnels are 

 visible with the aid of a hand-lens and there are no muscular strands attaching the 

 organs to the body- wall. Examined under the microscope, each tree is seen to possess 

 two longitudinal rows of minute ciliated funnels, the mouth of which does not exceed 

 0*047 mm - m breadth, while the length is not greater than o - i68 mm. The two 

 trees open separately into the intestine close to the anus. 



The alimentary canal is extremely long and intricately but irregularly coiled. 

 Its calibre is small at all points and the walls are thin and transparent. For a 



