Freshwater Bryozoa, with descriptions of new Species. 19S 



of the ovary*. In Fredericella a similar nucleated cell^ PI. II. 

 figs. 4 & 5 e, has been observed in the appendage to the 

 stomach, while the polype was yet in a very rudimentary state, as 

 exhibited in the bud before alluded to. In this genus I have 

 likewise seen the ovum in a considerably advanced state, in which 

 also its relationship to the ovary could not be mistaken. In this 

 instance the lower portion of the generative organ had dilated 

 into a sort of capsule, within which the q^^, PI. II. fig. 6 « & 

 PI. III. fig. 4 e, was enveloped. The portion of the ovary, PL II. 

 fig. 6 c, below it was short and thick, having the appearance of 

 a pedicle, by which the q^^ was fixed to the side of the cell ; 

 above the capsule, the ovary, c! , was much thinner, contracting 

 suddenly upwards. This would seem to demonstrate that the 

 egg is developed in the interior of the ovary. 



I have also seen what I take to be the ovum of Paludicella, but 

 as it differs considerably from the q^^ of the other freshwater 

 Bryozottj we must not pronounce with certainty. This supposed 

 t^^ was first observed in the cell of the dead polype ; two or 

 three occurred ; they were attached to the upper portion of the 

 interior of the cell. Afterwards one, PI. IV. fig. 7 e, was found 

 in connexion with the living animal, and in this case was fixed 

 by a delicate membranous sac, f\ to the side of the cell at the 

 point of attachment of the filament coming from the upper end 

 of the stomach, the base of the filament being apparently sur- 

 rounded by the sac. This filament then, in Paludicella, is pro- 

 bably an ovary ; and if so, the egg must pass in a very early stage 

 from it into the membranous sac at its base, and there be ma- 

 tured. And, judging from analogy, the other filament is also pro- 

 bably connected with generation. 



In Plumatella and Fredericella however there can be no doubt 

 of the ovarian character of one of the filaments attached to the 

 stomach; but the nature of the other two, PI. III. figs. 4/& 5 

 hj hj is not so easily determined. They certainly do not look al- 

 together unlike muscular fibres ; but from their attachments 

 close to that of the ovary, and from their resemblance to it, they 

 are most probably connected with the generative function. It 

 may be that each filament is a separate ovary, or that one or two 

 of them is the male organ. These polypes are most probably 

 hermaphrodites — at least, in all the specimens of Plumatella All- 

 mani that I have examined, there was scarcely a cell that did not 

 contain one egg or more. It may therefore be presumed that 

 each individual is provided with male and female organs. Dr. 

 Farre discovered moving bodies in the visceral cavity of Valkeria 

 and some other of the marine forms, and described them as re- 



* I have also seen a similar nucleated cell in the enlarged filament from 

 the lower end of the stomach of Bowerbankia. 



Aim. (Sf Mag. N. Hist. Ser. 2. Vol. v. 13 



