Rev. T. Hincks 07i British Pulyzoa. 217 



Genus Alcyonidium, Lamouroux. 



1. Alcyonidium disjunctum^ n. sp. 



Zoarium incrusting : zoooecia elongate-ovate, disposed in 

 linear series, which bifurcate at intervals and occasionally 

 anastomose ; the lines of cells bordered by a gelatinous crust ; 

 aperture small, placed near the anterior extremity ; cells often 

 massed together. 



Locality. Unknown. My specimens were received from 

 Mr. Alder. The cells differ much in shape from those of A. 

 mytili^ Dalyell, whilst the habit of the two forms is totally 

 dissimilar. 



The cells are much elongated and are linked together in 

 single series, and on each side runs a margin of the gelatinous 

 crust. The series bifurcate frequently, two lines originating 

 from the summit of a cell. At the bifurcation the crust forms 

 a web-like expansion between the two series. Every here and 

 there collections of cells occur, from which the single series 

 are given off. 



I have only had the opportunity of examining dried speci- 

 mens of this form ; and there is therefore a possibility that in 

 some points the characters may not be adequately represented. 



2. Alcyonidium lineare^ Hincks, MS. • 



This species is included by Mr. Alder, under the above name, 

 in his * Catalogue of the Zoophytes of Northumberland and 

 Durham.' I had corresponded with him about it, and had so 

 named it in my letters ; but no description of it has been pub- 

 lished beyond the brief notice which he has given in the 

 catalogue. In the meanwhile my specimens of it have 

 unfortunately perished, and I can add but little from my notes 

 or from memory to what he has written. 



It may be thus characterized : — Zoooecia oval, with promi- 

 nent tubular apertures, immersed in a gelatinous crust, dis- 

 posed in linear series, which generally branch from a central 

 mass. 



Localities. On mussel-shells from the Dogger Bank [T. H.) ; 

 CuUercoats, from deep Avater [Alder). 



Smith, in his ' Review of the Scandinavian Polyzoa,' ranks 

 this species as a hippothooid "form" of ^. hirsutum (Flem- 

 ing). But the zoooecium, which Prof. Smith will be the first 

 to recognize as the important element, is widely different in 

 the two, and separates them conclusively, apart from the very 

 characteristic and apparently constant habit. The tubular 

 aperture is very prominent and directed horizontally upwards, 



