532 



under the name of Spongia suberea. It is quite distinct from the 

 Sponge described under that name by Montagu ; and Dr. Johnston, 

 in the ' History of British Sponges,' refers the animal to the genus 

 Dysidea, with doubt, calling it D. ? papillosa (Sponges, 109, f. 18, 

 and t. xvi. f. 67). He at the same time expressed a belief that it 

 might be the nidus of some invertebrated animal, probably of a 

 species of Natica, and said that it " is nearly allied to the Alcyonium 

 ocellatum of Ellis and Solander (Zooph. p. 180, t. 1. f. 6) ; and it 

 is probable that the two productions are of the same nature, what- 

 ever this may be." 



Mr. Barlee has sent to the Museum some specimens in spirits and 

 dry, which he collected in 70 fathoms water near Shetland, and which 

 he, after comparing with Mr. Bean's specimen that was described 

 and figured by Dr. Johnston, considers as identical with that spe- 

 cies. Mr. Barlee observed that the animal was a Polype ; and the 

 examination of these specimens shows that Dr. Johnston's last ob- 

 servation is correct, and that the animal is very nearly allied to 

 Alcyonium ocellatum, and, instead of being the nidus of a Natica or 

 a Sponge, is a true Zoophyte, in fact, a Zoanthus allied to the 

 genus Mammillifera of Lesueur, to which the Alcyonium ocellatum 

 of Ellis is referred. 



The Zoanthi have been divided into three genera, according to the 

 manner in which the animals are united : — 1. Zoanthus, where they 

 are separate, and arise from a cylindrical creeping stem ; 2. Mam- 

 millifera, where they are equally separate, springing from an ex- 

 panded base ; and, 3. Corticifera, where the animals are united side 

 by side on an expanded base. Now the specimens described and 

 figured by Dr. Johnston evidently belong to the second of these 

 genera; but the animal described by Mr. Barlee as evidently belongs 

 to quite a different group : they are free ; and the stem often developes 

 lateral buds, giving it a more or less branched form ; and it is ne- 

 cessary that a new name should be applied to it : I therefore propose 

 to give the name of Sidisia, which may be characterized by the 

 emission of buds on the surface of the cylindrical body. 



Sidisia barleei, Mr. Barlee observes, " seems to abound on 

 muddy ground both east and north of Brassey Island, about thirty 

 miles off, and in about 70 or 80 fathoms water. The polype seems 

 generally very active ; and I saw no shifting of position of the ani- 

 mals while I had them in the basin, although there might have been 

 some during the night ; but I often watched them for half an hour 

 at a time, and perceived no change in position." 



As Mr. Holdsworth informs me that he is about to describe 

 another British species of the family which he has in a living 

 state, I have placed some of Mr. Barlee' s specimens in his hands, 

 and requested him to describe them at the same time. 



I may add that some years ago I had the ends of the siphons of 

 Cardium aculeatum, which had been torn off by a dredge, sent me 

 by an eminent British zoologist as a new kind of free Zoanthus ! 



