250 
Z. ASCIDIOIDA. 
Vesicularia. 
expanded, in which state it is of the same diameter as the rest of the cell ; but 
when the animal retracts is folded up and drawn in after it, and completely closes 
the mouth of the cell. 
“ The flexible part consists of two portions, the lower half being a simple 
continuation of the rest of the cell ; the upper consisting of a row of delicate 
bristle-shaped processes or setse, which are arranged parallel with each other round 
the top of the cell, and are prevented separating beyond a certain distance by a 
membrane of excessive tenuity, which surrounds and connects the whole. This 
mode of termination of the cell is one of constant occurrence, as will be describ- 
ed in other species, and is evidently a provision for allowing of the freest possible 
motion of the upper part of the body in its expanded state, to which it affords 
at the same time support and protection.” Phil. Trans, an. 1837, p. 393. 
22. Vesicularia, * Thompson. 
Character. Polypidoms rooted , confervoid, fistular, horny, 
dichotomously branched, jointed at the divisions : cells ovate , dis- 
junct, uniserial and unilateral. Polypes ascidian . 
1. V. spinosa. Dillenius. 
Plate xxix. Fig. 1-4. 
Conferva marina cancellata, Rail, Syn. i. 59, no. 11. Dill. Hist. Muse. 24, 
no. 22, pi. 4, fig. 22, — fide D. Turner in Lin. Trans, vii. 106 Con - 
ferva cancellata, Lin. Syst. ii. 720. With. Bot. Arrang. iv. 131 
Silk Coralline, Ellis , Corall. 20, no. 17, pi. 11, fig. b, B, c, D Ser- 
tularia spinosa, Lin. Syst. 1312. Ellis and Soland. Zooph. 48. Turt. 
Gmel. iv. 682. Jameson , in Wern. Mem. i. 564. Bose , Vers, iii. 118. 
Stew. Elem. ii. 446. Berk. Syn. i. 219. Turt. Brit. Faun. 215. La- 
marck, Anim. s. Vert. ii. 120. 2de edit. ii. 148. Hogg , Stock. 33 
Sert. sericea, Pall. Elench. 114 Laomedea spinosa, Corail. 91. 
Templeton in Mag. Nat. Hist. ix. 466 Valkeria spinosa, Elem. Br. 
Anim. 551 Vesicularia spinosa, Thomp. Zool. 111. 98, pi. 3. fig. 1-8. 
Farre in Phil. Trans, an. 1837, 401, pi. 22. La Laomedee epineuse, 
Blainv. Actinolog. 474. 
Hab. In deep water, not uncommon. “ Junio et Julio mensibus 
pone Sheerness in insula Shepey copiose observavi,” Dillenius. “ At 
the Nore, near the entrance of the Thames,” Ellis. Leith shore, 
Jameson. “ Rarely found near Hartlepool,” J. Hogg. “ Found 
on the shore of Belfast Lough : common,” Templeton. Liverpool, 
Rev. D. Landsborough. 
Polypidom affixed by a fibrous base, very slender, confervoid, of a 
thin membranous pellucid texture, much branched, erect, sometimes 
as much as 8 inches in height, usually about 4 ; main branches com- 
posed of intertwined capillary tubes, tapered, zigzag ; bran chlets arising 
from the bends, either solitary or in pairs, short, much divided dicho- 
tomously, the apices pointed and closed ; all the branches are joint- 
* From vesicula, diminutive of vesica , a bladder. 
