



376 THE GORGONIANS OF THE BRAZILIAN COAST. 



As in the case of the reef-corals, it is remarkable that any of the species shoi Id 

 be so closely allied to the West Indian species as we actually find them to b 

 considering the great distance separating the two faunae and the apparently 

 impassable barriers caused by the waters of the Amazon and Orinoco. As in 

 the case of the reef-corals 1 the relationship may be due to the conditions existing 

 in earlier geological periods, with a different coast line, and probably before the 

 Amazon and Orinoco existed in their present condition, and the Valley of the 

 Amazon was covered by the sea, as it appears to have been in the Cretaceous 



However, there are many cases of identical species among Echinodermata 

 and Crustacea, ranging from the reef regions of Brazil to the West Indies indi- 

 cating that those groups and others have had less difficulty in migrating or else 

 that they have changed less rapidly. 



It is not possible to believe that the migration has been southward from the 

 Antilles with the existing ocean currents flowing northward along the entire north- 

 ern coast of Brazil for 2,000 miles. Moreover, the freshening of the waters 

 for many miles beyond the mouths of the Amazon and Orinoco would probably 

 prove fatal to the delicate, free-swimming larvae of gorgonians and corals, thus 

 preventing migrations in either direction along extensive regions of the coast. 



So far as known, the larvae of gorgonians remain but a short time in the free- 

 swimming stage, and many, indeed, are viviparous. As in the case of the corals, 

 it is more probable that, in the instances of allied species, the Brazilian fauna is 

 the older, and that at some remote period migration to the Antilles was possible. 



The relations of the Brazilian gorgonians to those of West Africa and the 

 Pacific are very remote. 



Family MURICEID^ (Gray) Verrill, emended. 



Primnoacem (pars) Kolliker, Icones Hist., 1865, p. 135. 



Muriceidae Verrill, Bull. Mus. Comp. Zool., vol. XI, p. J 



XXXI, p. 92, 1889. Nutting, Monograph III, Sibo 



Wright 



) 



Armed or armored Gorgonacese with exposed external spicules, the outer 

 generally larger than the inner ones. Calicles usually prominent, commonly 

 with the margin armed with spinules; walls armed or unarmed, often plated. 



Ccenenchyma often spinulose, sometimes covered with a mosaic of thick 

 plates. Tentacles generally have opercular spicules on their bases. 



As here limited several genera usually referred to this family are excluded, 

 especially those that have an external layer of very small, short, granule-like 

 spicules, as in Astrogorgia and Heterogorgia, or an external layer of small clubs 

 perpendicular to the surface, as in Bebryce and Eunicella, (see under PlexauridfB) . 

 Anthogorgia, Stenogorgia, and Filigella are also excluded. 



The only shallow-water Brazilian genus is Muricea. The three species 

 known are not very nearly related to any of the several West Indian species, but 

 form a group by themselves. 



West 



Trans. Conn. Acad 

 q. West Indian an 



