ZOOPHYTOLOGY. 
249 
Doubts having been previously entertained witb respect to 
the distinction of this form from S. farciminoides, Mr. Alder 
found it necessary to subject both kinds to a careful re- 
examination/^ The result of which has confirmed him in the 
belief that they are really distinct species. The best charac- 
ter^ he says^ is found in the avicularium. This organ in S, 
farciminoides is semicircular and arched upwards ; that of S. 
sinuosa is triangular and points downwards^ always sloping a 
little to one side. In addition to this the form of the under 
lip of the cell differs in the two species : in S. farciminoides it 
is slightly arched in the centre ; whilst in S. sinuosa it is quite 
straight,, and rather projecting^ with a sinus at each end. 
We now quite agree with Mr. Alder in regarding the two 
species as distinct. 
Sub-order. Ctenostomata. 
Fam. Alcyonidiad^, Johnston. 
1. Alcyonidium. Lamx. 
1. A. mamillatmi, n. sp. Alder (p. 64, PL Y, figs. 3, 4). 
Encrusting, seniitransparent, brownish ; covered with rather long, stout, 
and strongly wrinkled papillse, from which the polypides issue ; tentacles 
16—18. 
Hab. On old shells, deep water. 
2. A, albiduMy n. sp. Alder (p. 64, PI. V, figs. 5, 6). 
Encrusting, semitransparent, yellowish- white ; general envelope incon- 
spicuous; polypides prominent, ventricose, flask-shaped, sub-recumbent, 
becoming erect towards the aperture, which is truncated when contracted; 
tentacles 18. 
Hab. The stem of Plum.falcata. 
2. Farrella, Ehr. 
1. F. pedicellata, n. sp. Alder (p. 68, PI. VI). 
Body (of cell) ovate-oblong, yellowish, transparent, with long and very 
slender pedicles, uniform in thickness throughout, arising from a creeping 
fibre ; tentacles 12. Length of cell, g'g inch. 
Hab. Old shells of Buccinum widatum and Fusus antiquus, in deep water. 
On some New British Polyzoa. By the Rev. T. Hincks. 
{Concluded from No. XIX, p. 176.) 
The following is the conclusion (accidentally omitted) of a 
paper which appeared in the last number of the ^ Journal.^ It 
completes the description of the Alcyonidium hexagonum 
(Hincks)— the A. Mytili of Dalyell. 
