215 



The genera Acrophytum, Spongioderma, IVIalacogorgia and 

 Trichogorgia appear to be peculiar to the district, and among 

 the pecuhar and characteristic species of the district may be 

 mentioned Alcyonimn purpureum, Sarcophytum trochiforme, 

 Gorgonia flammea, Gorgonia capensis, Eugorgia gilchristi and 

 Juncella spirahs. 



We have, therefore, assembled together in this region repre- 

 sentatives of the Indian Ocean, of the Atlantic Ocean, and 

 possibly in Alcyonium antarcticum a representative of the 

 Southern Ocean, but, at the same time, we find a considerable 

 number of species v/hich appear to be peculiar to the district. 



It may be of interest, for comparison with this statement, to 

 quote the following sentence from Agassiz's report on the 

 "Challenger" Echinoidea (p. 263). 



" The assemblage of species at the Cape of Good Hope is 

 most peculiar, it is the meeting of the western boundaries of the 

 African Indian Pacific and of the Indo-African, the southern 

 boundary of the Atlantic and the northern extreniities of tiie 

 Southern Ocean faunae, and it has no species characteristic of 

 its own in the continental or abyssal range." 



Family Alcyoniidae. 



Alcyonium purpureum, n.sp, 



Plate VII., fig. I. Plate IX., fig. 18. 



Locality : Jetty at Mossel Bay. 



Some specimens of this Alcyonium growing upon Tunicate 

 tests and worm tubes were tal^en from the piles of the jetty at 

 Mossel Bay. Dr. Gilchrist states that he has found the same 

 species in Saldanha Bay. With some hesitation I have decided 

 to constitute for them a new species. They are clearly distinct 

 from the A. pachyclados described in my last contribution (6), 

 and they are also distinct from A. antarcticum, which they re- 

 semble superficially in some respects. They appear to differ 

 from all species of the genus about which we have adequate in- 

 formation in the fact that, when alive, they are of a brilliant 

 purple colour. Dr. Gilchrist tried all sorts of expedients, in 

 vain, to get the specimens to retain their colour. Sometimes 

 he seemed to have succeeded, but when the colony was apparently 

 quite dead, the pigment would pour out into the preservative 

 fluid in streams. I do not call to mind any description of a 

 species of Alcyonium in which a soluble colour of this kind is 

 mentioned, and I have never noticed anything of the kind in 

 the living specimens I have examined. In the British speci- 

 mens of Alcyonium digitatum there is frequently noticed a pale 

 pink colour, which gradually fades when the colonies are pre- 



