Art. IX. — Notet^ on the Mode of Reprodactlov of Geone- 

 ■mertt's austraHenNis. 



By Arthur Dendy, D.Sc, Univevsit}' of Melbourne. 



[Read October 13, 1892. j 



In the paper on Geonemertes austral lens Is* which I had 

 the honour of reading before this Society hist year, I shewed, 

 by anatomical examination, that in this w^orni the sexes ai'e 

 not united in the same individual, but that distinct males 

 and females exist. The males, however, appeared to be 

 much less common than the females and the single one which 

 I obtained was considerably below the average size, though, 

 from the insufficiency of the data, it was impossible to found 

 any generalization upon this fact. At the time when I wi'ote 

 I had made no observations either as to the mode of copula- 

 tion of male and female or as to the manner in wliich the 

 eggs are deposited. Relying upon m}^ anatomical investiga- 

 tions, however, I ventured to indulge in certain speculations 

 on these points, which ai'e contained in the following 

 paragraph : — 



" The ova, as already stated, grow to a very large size, 

 Ineasuring up to about O'G mm. in diameter. It seems to me 

 ahiiost impossible that they should be discharged through 

 the narrow, preformed genital ducts. I believe that they 

 escape by rupture of the body wall and that the ducts merely 

 serve to convey spermatozoa to them. That these ducts do so 

 convey the spermatozoa I conclude from the fact that I have 

 found spermatozoa in them. Probably the process of 

 fertilization is effected by the male crawling over the female 

 and passing out the sperm as he crawls."-f- 



Since this was printed my friends Messrs. C. C. Brittlebank 

 and H. Giles have collected specimens of Geonemertes 

 australiensis and also made some extremely interesting 

 observations upon the method of copulation and egg-laying. 

 I have to thank these gentlemen, not only for an account of 

 their observations, but also for sending me the specimens 



* " On an Australian Land Nemertine {Geononcrtes aii^traUensix, n. sp.)" 

 Proc. Koyal Soc. Victoria, Vol. IV, N.S., p. 85. 

 + Loc. cit., p. 115. 



