THE ALC YON ARIA OF THE CAPE OF GOOD HOPE AND NATAL. 571 



thickly beset with short calcareous spicules, especially double-clubs, ordinary clubs 

 and spindles, so that it acquires a thick leathery consistence." 



In the Museum of Natural History, Berne, Ehrenberg's type specimen of Lobular ia 

 pachyclados is preserved, and I have been able to compare it with the specimen here 

 described. 



My specimen agrees well with the description and figures of Alcyonium pachy dados, 

 Klunzinger, but in his account there is no information regarding the anatomy. As 

 my specimens were sufficiently expanded to enable me to count the number of pinnules, 

 this and other points may prove of systematic value. 



Hickson had a red, a yellow, and a white specimen from the Cape. The red speci- 

 men was a female, the yellow specimen a male, and the white specimen apparently in a 

 neutral condition. In my case, the specimens show the reverse, the female being yellow 

 and the male red ; thus the colour is obviously not to be regarded as a sexual character. 



Thomson and M'Queen (1908) record Alcyoyiium spha>rophorum (Ehrenberg) 

 from the Sudanese Eed Sea, a species originally described from that locality by 

 Klunzinger. The authors suggest the incorporation of A. pacliyclados and A. 

 sphwrophorum as one species. They are also inclined to think that A. globuliferum, 

 Klunzinger, A. digitulatum, Kl., A. brachy dados, Ehrenberg, and A. pachyclados, Kl., 

 should all be referred to one species, viz. A. sphcerophorum. 



May has recorded A. pachyclados from Albay (Luzon) and from Zanzibar. Pratt 

 has personally examined and compared forms of Alcyonium pachyclados from 

 the Cape with specimens of the same species from the Maldives and New Britain, 

 which are found to be identical with Alcyonium pachyclados, KL, from the Red Sea. 

 The author finds that the forms of this species from the Cape, Maldives, and New 

 Britain agree with one another in all important features, only differing in form and 

 colour. Pratt therefore holds that here we have identical forms collected from 

 tropical waters and a temperate ? region (the Cape), and that therefore one can no 

 longer regard Alcyonium as an extra-tropical genus. From this fact and the 

 somewhat vague diagnosis of Lobularia, Pratt maintains that this genus should 

 be deleted from the family Alcyonidse. The point on which I mainly disagree with 

 Pratt's argument is that of regarding South African seas as necessarily temperate. 

 As a consideration of isothermic lines will show, the water temperature on the east 

 coast of South Africa is at the least only on the border between tropical and temperate. 



The forms of A. pachyclados compared by Pratt were found in the Ped Sea, in 

 tropical seas, or in a region influenced by tropical currents. A warm tropical current 

 flows from the Indian Ocean down the east coast of Africa (where these forms of 

 A. pachyclados occur). This warm current, known respectively as the Mozambique, 

 Natal, and Agulhas currents, influences the nature of the fauna on the east coast of 

 South Africa. Gilchrist has pointed out examples showing the difference between the 

 fauna on the warm east coast, as compared with that on the west coast, where the 

 fauna is influenced by the cold Benguela current. 



