CYLINDIICECIUM GIGANTEUM. 535 



Genus CYLINDRGECIUM. 



Der. From KvXivSpos, a cylinder, and oikiov, a house. 



Farrella (part.), Busk : Gosse: Hincks. 

 AvENELLA, Alder : Hincks : Gosse {not Dalyell). 

 Valkeria (part.), Smitt. 



Generic Character. — Zocecia elongate, cylindrical, 

 crowded together or scattered, rising from a creeping 

 stolon. PoLYPiDE without a gizzard. 



CyLINDR(ECIUM GIGANTEUM^ Blisk. 

 Plate LXXYII. figs. 3, 4. 



Fabrella gigantea, Busk, Quart. Journ. Micr. Sc. ir. 93, pi. v. figs. 1, 2; 



Go&sc, Mar. Zool. pt. ii. 22, fig. 40. 

 Avenella gigantea, Hincks, Dey. Cat., Ann. N. H. ser. 3, ix. 473 (59, 



Sep.). 



Zooecia tubulous, thickly crowded together, the walls ren- 

 dered dark and opaque by imbedded earthy matter, of 

 great length (occasionally more than §■ inch), not de- 

 cumbent at the base. 



Polypide with 18-20 tentacles. 



In a specimen of this species from Tenby, which I owe to 

 Mr. Busk, the cells are densely croAvded together on the 

 stolon ; and he describes it as " growing in a close and 

 thick pile " on the walls of the cave where it was disco- 

 vered. The length of the cell is remarkable, and also the 

 opacity of the ectocyst, due to the very large quantity of 

 earthy matter with which it is charged. I have never 

 been able to detect any dilatation of the stem at the base 

 of the zooecia in C. giganteum. 



Habitat. On rocks near low-water mark. 



Locality. Tenby (Busk). 



