455 



the worm at the time of sexual maturity. In at least three of these 

 eight forms [Oeonemertes chalicophora Graffs, G. iiovae-zealandiae 

 Dendy and O. graffi Bürger) the males have not as yet been disco- 

 vered, although the worms habe been supposed to be separate sexes. 

 In O. australiensis Dendy both sexes have been observed, the males 

 being much less common and of smaller size than the females. In 

 G. rodericaiia (Gulliver) the sexes are likewise separate. Only a single 

 species of the genus ( G. palaensis Semper) has hitherto been found to 

 be hermaphroditic, although Graff's original description states that 

 such is the case in G. chalicopliora. Böhm ig, however, after an exami- 

 nation of Graff's specimens decided that the latter species is actually 

 dioecious. None of them have hitherto been found to be viviparous. 



An examination of large numbers of sexually mature individuals 

 of the Bermuda Land Nemertean [G. agricola W.-Suhm) has revealed 

 several interesting features in regard to its sexual phases, for this spe- 

 cies proves to be not only hermaphroditic but also viviparous. 



In the months of June and July the majority of the individuals 

 contained embryos of such large size and in such numbers as to 

 encroach largely upon the intestinal canal, proboscis sheath, and other 

 organs, and to distend the body walls nearly to the point of rupture 

 (Fig. 1, 2). The most remarkable feature of such individuals, however, 

 lay in the fact that in addition to the large embryos they possessed very 

 small gonads of which some contained immature ova and others sper- 

 matozoa in all stages of formation. 



Other individuals of much smaller size were filled with large sper- 

 maries with mature spermatozoa, but were without indication of ovaries 

 or embryos. Such individuals, representing the purely male phases, 

 were much less common than those with eggs or embryos, occuring in 

 about the proportion of 1 to 1 2. 



Specimens collected in April and sent alive to the writer contained 

 no embryos, nor did any of them indicate that they were hermaphro- 

 ditic. They all appeared to be of the female sex and were provided 

 with large and nearly ripe ova. They may be considered as represent- 

 ing the purely female phase of sexuality. They were without exception 

 of large size for the species, and it is possible that the much smaller 

 males may have been present in the same locality and were overlooked 

 by the collector. 



Somewhat later in the season hermaphroditic forms appear, some of 

 which first discharge their spermatozoa and then form ova, which, after 

 fertihzation by another individual, develop into embryos within the 



1 According to Böhmig, Ztschr. f. wiss. ZooL, Bd. LXIV, S. 484, 1898. 



