348 ON A HERMAPHRODITE AND 



were undergoing multiplication or prolification, by a process which 

 can only be described as a combined fission and gemmation. The 

 prolification takes place so as to separate all the segments of the 

 parent behind the sixteenth, as a new zooid ; but it is not a mere 

 process of fission, for the seventeenth segment, i.e., the first of the 

 new zooid, undergoes a very considerable enlargement, and eventually 

 becomes divided into the nine segments of the head and thorax, of 

 the bud. These segments do not appear all at once, but gradually, 

 one behind the other. The intestinal canal of the stock and of the 

 bud are at first perfectly continuous, but the peri-intestinal cavity of 

 the bud is completely filled with a mass of red granules. These 

 would seem in some way to subserve the nutrition of the young 

 animal ; for in some free zooids, apparently fully formed, all but the 

 development of genitalia, the caudal segments were full of these 

 •orange granules, while no trace of them was to be found anteriorly.^ 



It is very interesting to note the manner in which the branchial 

 plumes are developed, as it closely corresponds with what Milne- 

 Edwards describes in Terebella. Each plume appears at first as a 

 ■quadrate palmate process of the dorsal side of the first segment ; and 

 the divisions representing the stems of the future branchiae are at 

 first mere processes, — perfectly simple tubes, which do not even 

 present annulations. 



Several modes of prolification are already known to exist among 

 the annelids. The one long since described by O. F. Miiller, as one 

 of the methods of multiplication of Nais, and more lately by 

 Quatrefages as occurring in Syllis prolifera is very nearly simple 

 fission, the animal dividing near its middle, and the under half, before 

 separation, only putting forth, as buds, those appendages which are 

 characteristic of the head. 



Secondly, Milne-Edwards has described in MyiHadina a prolification 

 by a sort of continuous budding between the anal and the penultimate 

 segment. A new ring is produced behind the penultimate segment, 

 and this enlarging gives rise to a new ring posteriorly, and so on until 

 the bud attains its full length. 



It would seen possible that the second mode of prolification in 

 Nais, described by O. F. Miiller, is in reality the same as this, though 

 he describes the new growth as entirely resulting from the excessive 

 development of the anal segment. 



Thirdly, M. Schulze, an excellent observer, has described a third 

 very singular mode of prolification in Nais, whence the long chains of 



' Sars gives an account of the prolification of Filograna implexa, similar in all essential 

 points. See his Fauna littoralis, &c., pp. 88-9. 



