ENTEROPNEUSTA FROM MADRAS. 127 



one on the ventral side. As in other forms, these are, no 

 doubt, caused by the contraction of the dorso-vcntral septum 

 of the proboscis. The anterior extension of the groove 

 shows that the septum is not confined to the base of 

 tlie proboscis. The proboscis is connected with the collar 

 by a very thin neck. The collar measures nearly 1 mm. in 

 length and nearly H mm. in breadth. Three annular 

 grooves are present. The branchial region, which, like the 

 collar, is nearly cylindrical, measures about 1^ mm. from side 

 to side. The larger of the specimens possessed about 18 mm. 

 of this region, which was coiled ventrally, as shown in fig. 2. 

 The sides of the trunk were transversely ridged, the ridges 

 becoming more marked posteriorly. 



The dorsal surface of the truuk is slightly flattened, and 

 has a shallow, median, longitudinal groove containing' the 

 nerve-cord, and on either side of it a submedian groove con- 

 taining the branchial pores and the openings of the gonads. 



Both specimens were female, and were of a light brown 

 colour. The tip of the proboscis and the collar were yellowish 

 in colour. 



I have not been able to make a complete study of the 

 internal anatomy, but certain interesting points maybe noted. 



Proboscis. — The circular muscle is, as is usually the case 

 in this genus, feebly developed. The longitudinal muscle 

 forms a very thick layer, the fibres of which are not 

 arranged in concentric rings. In this latter point, the 

 present species agrees with otagoensis. The fibres have 

 a remarkably straight course, as they are almost all repre- 

 sented by dots in transverse sections. The cavity of the 

 proboscis is not merely confined to the base, but is present 

 throughout the whole length of the proboscis. It is fairly 

 wide — half as wide as the proboscis itself — in its anterior 

 third, but between it and the base is reduced to a very 

 narrow caiuil. At the base, the cavity is present as a very 

 narrow space investing the basal organs in the usual way. 

 The basal organs project a very short distance — about one 

 tenth of its length — into the proboscis. The median mesen- 



