CYLINDRCECIUM GIGANTEUM. 535 



Genus CYLINDRCECIUM. 



Der. From KvXivSpos, a cylinder, and o/riov, a house. 



FARHELLA (part.). Busk : Gosse : Hincki. 

 AVENELLA, Alder : Hincks : Gosse (not Dalyell). 

 VAI.KEKIA (part.), Smitt. 



GENERIC CHARACTER. ZOCECIA elongate, cylindrical, 

 crowded together or scattered, rising from a creeping 

 stolon. POLYPIDE without a gizzard. 



CVL1NDR(ECIUM GIGANTEUM, Busk. 

 Plate LXXVII. figs. 3, 4. 



FARRELLA GIOANTEA, Busk, Quart. Journ. Micr. Sc. iv. 93, pi. v. figs. 1, 2: 



Gosse, Mar. ZooL pt. ii. 22, fig. 40. 

 AVENELLA ciGAXTEA, Hincks, Dev. Cat., Ann. N. H. ser. 3, ix. 473 (59, 



sep.). 



Zocecia 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 crowded 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. Trnliy (Busk). 



