120 R. C. PUNNETT. 



the tip of the snoiit^ and the ducts commence about this level 

 also. The system is interrupted in many places. These ducts 

 are exceedingly numerous, far exceeding in number those of 

 any other Nemertine known. On one side I was able to count 

 nearly a hundred ducts, and even then the excretory system 

 had not come to an end. Another feature peculiar to this 

 worm, and one which, so far as I am aware, occurs in no other 

 member of the group, is the backward extent of the excretory 

 system into the intestinal region, where the geaierative sacs 

 and their ducts also occur. Their extent may be more easily 

 recognised by a glance at the table below giving the levels 

 at which various systems commence or terminate. All sections 

 are 5 n in thickness. 



Commencement of brain 

 Commencement of cerebral organ 

 Termination of cerebral organ . 

 Commencement of excretory system 

 Termination of oesophagus 

 Commencement of generative region 

 Excretory system still found in 



In the generative region the excretory tubules have almost 

 disappeared, though traces of them may still be recognised 

 (ho-. 10 "^j. The excretory ducts are in this region often 

 incomplete, not penetrating the circular muscle layer. Their 

 external opening, however, appears to be always present. As 

 these ducts and the gonads are found in the same region, it 

 seemed possible that the former might, where present, act as 

 the ducts of the latter. Such a view, however, appears to be 

 negatived by the following considerations : 



(1) The ducts which are seen to be in connection with the 

 gonads show a diiferent histological structure, being composed 

 of long fibrillated cells with slender rod-like nuclei (fig. 10, 

 gel.). The excretory ducts do not present this fibrillated 

 structure, and their nuclei are smaller and slightly oval 

 fig. 10, exd.). 



