COLLECTION OF NEMERTEANS FROM SINGAPORE. 135 



worth venturing a suggestion as to their origin. A ventral 

 gutter is not present. 



The proboscis is lacking. 



The proboscis sheath ends rather more than 1 cm. from 

 the posterior extremity. 



The generative sacs contain nearly mature ova. 



The excretory system commences before the end of the 

 cerebral organ. The system is short, and opens by a duct on 

 each side which passes a little dorsal to the side stem. 



The nervous system is in no way remarkable. The 

 dorsal lobe of the dorsal ganglion is large, but does not reach 

 as far as the cerebral organ. 



The cerebral organ is short, and the dorsal glands are 

 not strongly developed (fig. 34, a — d). 



The frontal organ is well marked. 



Eyes are not present. 



The head glands are fairly strong, and reach backwards 

 about halfway to the brain, where they end abruptly. 



Before bringing this paper to a close it may be as well 

 briefly to summarise the points of more general interest which 

 have arisen in connection with this collection. 



(1) A considerable amount of variation occurs in the 

 striking and characteristically marked Eupolia melano- 

 gramma, and such variation appears to be continuous rather 

 than discontinuous. 



(2) The excretory system of E. melanogramma possesses 

 the hitherto unique feature of ducts opening into the alimen- 

 tary canal. 



(3) In E. pholidota the excretory ducts reach back into 

 the intestinal region, thus co-existing in the same region with 

 the gonidial ducts. Histological evidence tends to show that 

 these two sets of ducts are not homodynamous. 



(4) In the same genus (Eupolia) the lateral nerve-stems 

 may form a commissure either above or below the anus, or 

 else may end blindly. 



