406 On the Victorella pavida of Saville Kent. 



the fact that we have here a form intimately allied to, if not 

 identical with, some marine forms, and differing widely from 

 the freshwater types, but which yet with its host appears to find 

 itself perfectly at home in fresh water. Mr. Shepherd has, 

 since seeing my specimens, found it in the Regent's Canal at 

 Maida Vale; and I have found it in the Surrey Canal, unac- 

 companied by any other marine type, or even one found largely 

 in brackish water, except Pleurosigma. 



The small number of tentacles, their setigerous character, 

 the complete extrusion of the polypide, the absence of epi- 

 stome, and the striated muscular fibres are distinctly different 

 from the freshwater type, and are constant characteristics of 

 the marine type. Much remains to be done before the con- 

 ditions under which this and similar transfers of marine forms 

 to freshwater habitats are understood. 



It will be seen that my observations differ from Mr. Kent's 

 as to the character of the polypidom of Victorella^ the presence 

 of the gizzard, and the nature of the operculum, while, pro- 

 bably from not using sufficient magnification, he did not 

 make out the setse upon the tentacles and apparently did not 

 see the typical form of Victorella at all. 



In conclusion, I have to acknowledge much kindness 

 received from Prof. Allman and Mr. Pennington (whose 

 work on the British Polyzoa is, I believe, about to appear). 

 The latter gentleman relegates Victorella to the family Cylin- 

 droeciidge, and has kindly drawn up the following diagnosis : — 



Genus Victorella. 



Characters as Cylindroecium, but polypides transparent and 

 having a gizzard. Tentacles eight. 



Victorella pavida J S. Kent. 



Stem repent, slender, orange-coloured during life, trans- 

 parent after death ; clavate enlargements wide apart. Zooecia 

 with upper portion erect, cylindrical, transparent, slender. 

 Below adherent and dilated, forming part of the stolonic 

 expansions. 



Hah. Brackish and fresh water, on Cordylophora lacustrisy 

 whose migrations it follows. 



EXPLANATION OF PLATE Xn. Figs. 1-3. 



lig. 1. Portion of stolon at growing end, showing the lateral branches 

 and young zooids. a, zooid extended ; b, zooid developing ; 

 c, euibrjonic zooid at end of branch; d, funiculus. 



