NORTHUMBERLAND AND DURHAM. 105 



to detect on account of the species being very much mixed up 

 with other parasites, especially Alcyonidium mammillatum. The 

 number of tentacles is not very constant, varying with age, and 

 occasionally reaching sixteen, but ten is the more usual number. 

 The mouth is conical when at rest, but varies much in form, 

 sometimes expanding into a flat disc with a wide aperture, simi- 

 lar to what is occasionally seen in Hjjdracthiia echinata, to the 

 polype of which this bears a strong resemblance. 



Mr. Howse has favoured me with the examination of a zoo- 

 phyte, parasitical on the operculum of Fusus Norvegicus^ which 

 is more than twice the size of this and more flexible, having much 

 the appearance of a distinct species ; but as I can find no essen- 

 tial difference in the form and mode of branching of the polypary 

 (the only part remaining), it must be considered, for the present 

 at least, to be a large variety of the same. 



Another form has lately occurred to me more branched than 

 that described above, and showing at the top of the tube a cup- 

 like expansion, similar to what is represented by M. Van Beneden 

 in his E. ramosum. The cup, though continuous with the tube, 

 is more membranous, and soon falls off. The basal part is less 

 ramified. I am unable to say, at present, whether this should be 

 considered a variety or a distinct species. It may possibly be 

 the same with that described by M. Van Beneden under the 

 name of E. ramosum^ but it is not the Tuhularia raTnosa of Lin- 

 neeus, of which Ellis's figure must be considered to represent the 

 type. 



4. E. CAPILLARE, 71. Sp. PI. III., fig. 9 12. 



Polypary minute, very slender, thread-like, a little branched, 

 transparent, pale horn-coloured, smooth, excepting two or 

 three faint rings near the origin of each branch. Polypes 

 terminal on the upper branches, vase or pear-shaped, with 

 a single row of eighteen or twenty long slender tentacles ; 

 reproductive capsules on separate short branches near the 

 lower part of the stem, on clustered or verticillate pedi- 

 cles, two or three capsules in linear series on each pedicle. 

 Height \ inch. 



