Manchester Memoirs, Vol. Ixii. (191 7), No. 7 



VII. The Occurrence of Cavernularia Lutkenii, Koll. 

 in the Seas of Natal. 



By J. Stuart Thomson, M.Sc, Ph.D., F.R.S.E. 



Lecturer in Zoology in the Victoria University of Manchester. 

 (With one text-figure and two plates). 



Genus Cavernularia Valenciennes. 

 Cavernularia Milne-Edwards & Haime. Hist. nat. Coralliaires, 1857, Vol. I. p. 219. 

 Cavernularia + Sarcobelemnon Herklots. Polypiers nageurs, 1858, p. 25. 

 Cavernularia + Stylobelemon Kolliker. Die Pennatuliden. 1872, pp. 336 and 348. 

 Fusticularia Simpson. Ann. N. H. 1905, p. 561, PI. XVIII. 



In a paper on the Pennatulacea of the Cape of Good Hope 

 and Natal contributed to the Memoirs and Proceedings of the 

 Manchester Literary and Philosophical Society I gave an 

 account of those forms collected by the Cape Government 

 trawler, the Pieter Faure. In preparing a second paper on 

 the Alcyonaceous species from the same locality, I find that 

 I have overlooked two specimens of Cavernularia Lutkenii, 

 Koll. and I therefore now record this species from Natal and 

 add descriptive notes. 



The two parts, the stalk and the rachis pass almost imper- 

 ceptibly into one another, on the latter numerous autozooids 

 occur, with many siphonozooids between them. The smaller 

 specimen has contracted in such a manner that the rachis which 

 in the larger example is more or less hemispherical, is rather 

 club-shaped. The stalk is soft and bladder-like; the colour of 

 the specimens is cream. 



The stalk of the larger specimen is 40 mm. in length, 6 by 

 7 mm. in diameter near the apex, 11 mm. at the middle of its 

 length and much narrower at the base. The rachis of the 

 larger specimen is 34 mm. in length, and its greatest diameter, 

 namely, near the middle of its length, is about 33 mm. The 

 autozooids are very delicate, and almost transparent. In the 



