3fisceUaneons. 311 



were formerly mistaken for buds, but evidently result from the 

 dehiscence or separation of branches which leave the parent stock 

 to establish colonies elsewhere. Though I have not observed this 

 separation take place in Uniafella, yet all the points of structure 

 appear to indicate that it actually takes place in the manner inti- 

 mated. 



It thus appears that the first step towards the multiplication of 

 Umatella is the segmentation of its stem. The segments put forth 

 buds which develope polyps, and these then separate from the 

 parent stock to settle elsewhere and become the source of other 

 series of polyps. 



The ultimate history of the segmented polyp-stock of Umatella I 

 have not ascertained. The stocks which I have preserved in an 

 aquarium for several months finally lose their terminal polyps. 

 Late in the season, also, all the polyp-stocks which I could obtain 

 on the river-shore within the reach of my arm, at low tide, were 

 deprived of their terminal pol^'ps. The destruction of these, how- 

 ever, I have suspected to have been due to their having been un- 

 covered in lower tides earlier in the season. I hope yet to be able 

 to determine this question in the course of the next few weeks. 



It has occurred to me that the segmented stems of Umatella, after 

 the decay of the polyps, remained through the winter with little 

 obvious change, and that in the following season the segments 

 served as reproductive bodies, in the same manner as the statoblasts 

 in Plumatellidfe and their allies. This view, however, is not con- 

 firmed by specimens retained in the aquarium and those collected 

 on the edge of the river which had lost their polyps. 



In relation to the production of ova, or the reproduction of Uma- 

 tella through sexual agency, I have yet learned nothing. 



Among the animals mentioned as found in association with Uma- 

 tella is the singular Annelide Manayunkia spedosa, discovered by 

 me some years ago (Proc. Acad. Nat. Sc. 1858, p. 90). The worm 

 is closely allied to the marine genus Fabricia, and, like it, lives in 

 tubes constructed of mud. It is abundant in the locality indicated. 

 Individuals about two lines in length are usually seen in a state 

 of division near the middle into two. The anterior division of the 

 body consists of five bristle-bearing annuli in addition to the head. 

 The posterior division consists of six bristle-bearing annuli in addi- 

 tion to the partially developed head. The anterior head is provided 

 with about thirtj-six ciliated tentacula supported on four lobes. It 

 is also furnished with a pair of e^^es ; besides which the tentacle- 

 bearing lobes exhibit a number of pigmentary spots, apparently of 

 the nature of eyes. No eyes exist in the tail of Manaijmikia as 

 they do in Fabricia. The blood is green, and is pumped intermit- 

 tently into a large vessel occupying one tentacle on each side of the 

 middle of the head. 



I have studied the development of Manayunkia, which will be 

 fully described in a future memoir on the animal. Curiously enough, 

 the development of the young takes place within the tube of the 

 parent, and the young remain in this position for a considerable 

 time after their development. Thus I have obtained the young 



