28 THE VOYAGE OF H.M.S. CHALLENGER. 



Similarly on the west coast of America, species of Leptogorgia, which are there very 

 plentiful, grow within these limits, associated with Muricea and Eumuricea. 



Among the Coral Reefs of the Pacific and Indian Oceans a large number of species is 

 to be found growing within this littoral zone to a depth of 10 fathoms. By far 

 the greater number of these belong to the genera : — Sympodium (Cornularidse) ; Tubipora 

 (Tubiporidae) ; Xenia (Xenidse) ; Lobularia, Lobophytum, and Sarcophytum, among the 

 Alcyonidse ; JSfephthya, Ammothea, Spongodes, among the Nepthyida? ; and Heliopora 

 among the Helioporidse. 



In the deeper water, down to 100 fathoms, there predominate in the northern seas : — 

 Clavularia and Sympodium (Cornularida?) ; Anthomastus, Alcyonium (Alcyonidse) ; 

 Gersemia, Eunephthya, Duva (Nephthyidse) ; Anthothela, Paragorgia (Scleraxonia) ; 

 Paramuricea, Danielssenia, and Primnoa (Holaxonia), the last at depths below 

 50 fathoms. 



On the eastern shores of the North Atlantic and in the Mediterranean, the following 

 genera are particularly frequent : — Alcyonium, Bellonella, Corallium, Paramuricea, 

 Bebryce, Eunicella (the last on the whole east coast of the Atlantic, as far as the 

 Cape of Good Hope), Leptogorgia, Gorgonia. Here also, below 50 fathoms, are found 

 Primnoidse, like Primnoa and Caligorgia, with Isidella among the Isidae. 



On the west coast the predominant forms are Anthothela, Titanideum, Leptogorgia, 

 and Gorgonia. 



The east coast of the Atlantic equatorial region is not rich in species, while such as occur 

 resemble those of the temperate seas, a fact which is to be explained by the relatively low 

 temperature of the water off the west coast of Africa. The species so far known belong 

 to the following genera : — Scleranthelia, Bellonella, Paramuricea, Eunicella, Gorgonia, 

 Leptogorgia, Juncella, Verrucella. 



To the west, on the coasts of Brazil and the West Indies, there are many genera 

 well represented by numerous species :• — Anthelia, Telesto, Acanthogorgia, Hypnogorgia, 

 Villogorgia, Muricea, Acis, Thesea, Eunicea, Plexaura, Plexaurella, Pseud oplexaura, 

 Gorgonia, Leptogorgia, Phyllogorgia, Verrucella, Juncella. There are also, in the 

 deeper water below 50 fathoms, Caligorgia, Paramuricea, Placogorgia. 



In the south temperate region of the Atlantic, about the Cape of Good Hope, 

 representatives occur of the genera : — Anthelia, Eunephthya, Spongioderma, Eunicella, 

 Platygorgia, Lophogorgia, Gorgonella, Euplexaura, Lsidella. 



In the temperate regions of the west coast are found Suberia and, in the deeper water 

 below 50 fathoms, Primnoella. 



In the Pacific Ocean this zone is characterised along the whole west coast of America 

 by the predominance of the Muriceida? and Gorgonidse, which there exhibit the maximum 

 number of species. Thus the genera Muricea and Eumuricea, together, include fifteen 

 species ; Heterogorgia is represented by three species, Psammogorgia by four species, 



