738 OBSERVATIONS ON SOME AUSTRALIAN POLYCH^TA, 



of columnar cells, which, thickly pigmented internally, are 

 continuous externally with fibres passing into the substance of the 

 cerebral ganglia. 



The segmental organs are curved brown tubes opening on the 

 venti-al surface close to the parapodia. The function discharged 

 by these organs in Syllis seems not to have been positively 

 ascertained. No doubt they act as generative ducts, but neither 

 INIecznikow, Ehlers, nor Claparede, who have all noticed or 

 described the organs, mentions having observed them giving passage 

 to ova or spermatozoa. 



This species increases like many of the Syllidce, by a combination 

 of budding and fission ; and exhibits some remarkable peculiarities 

 iu connection with the processes of reproduction. In specimens 

 obtained from between tide-marks in Port Jackson, about the 

 month of August, I found none in the act of proliferation ; nearly 

 all, however, showed a marked division of the body into two 

 regions — a long dark-coloured female region, in which the body 

 cavities of most of the segments contained ova, and a much 

 shorter, posterior orange-coloured male region, in which the sexual 

 glands wei-e imperfectly developed testes. The passage from the 

 one region to the other takes place somewhat abruptly about the 

 100th segment, the body at this point becoming narrower, and 

 both the parapodia and the dorsal cirri smaller. In specimens 

 taken at the same time in deeper water, the posterior orange- 

 coloured region was found to be considerably longer ; in most it 

 had developed on its first segment two pairs of large eyes, and 

 frequently was found altogether detached from the female. The 

 following is a description of the curious male form thus produced 

 by budding from the posterior end of the female : — 



The colour is reddish orange, finely mottled with dark brown along 

 the middle of the dorsal surface. The length is an inch, the breadth 

 a fifth of an inch. There are forty-five segments, but some of the 

 posterior segments appear to be wanting in the specimens I have 

 examined. The head is very broad, broader than the body-segments, 

 and very short; its anterior border is concave. In the middle of this 

 concavity, on the ventral aspect, is a shoi't ciliated process, and on 



