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Notes on Plymouth Hydroids. 



By 



C. C. Nutting. 



Professor of Systematic Zoology in the University of Iowa. 



The following notes are based upon observations made during April 

 and the first half of May, 1895. Although the Plumularidos were the 

 special objects of study, a number of facts concerning other forms 

 were noticed, which, together with the discussion of certain matters 

 brought out in the special study of the Plamularidce, were considered 

 by the Director to be of sufficient interest for publication in this 

 Journal. It will be understood that no general discussion of the 

 hydroids at Plymouth is attempted, nor is it my purpose to give a list 

 of the hydroid forms of that exceedingly rich field, no species being 

 mentioned unless some new fact has been observed concerning it, 



EUDENDRIUM ALBUM, n. Sp.* 



Hcibitat. On stones in shallow water near Millbay Channel. The 

 stones are often covered with a dense growth of this hydroid, which 

 appears to the unaided eye like white cottony tufts or downy patches. 

 The gonophores were abundant in April. 



The distinguishing features of this species are the minuteness of the 

 colony and of the individual hydranths, both of which are less than 

 half the height of any other Eudendrium from British waters, and the 

 very striking white colour of the hydranths, a feature not found in any 

 other Eudendrium in that locality. Eudendrium album is one of the 

 most abundant hydroids at Plymouth during the spring, where it has 

 heretofore been regarded as Eudendrium capillare, Alder. It seemed, 

 however, so different from the descriptions and figures of that species 

 given by Alder, Hincks, and Allman, that specimens were sent to the 

 veteran authority on hydroids — Professor Allman — who regarded it as 

 probably new, and advised the writer to describe it as such. 



• This is the species referred to by Allen, vol. iv. no, 1, p. 49, of this Journal. A full 

 description, with figures, will shortly be published in Ann. and Mag. Nat. Hist, 



