SPONGITDA. 583 



representing the African coast) ; 2. Glorioso Islands (as the- most 

 southern investigated memher of the outlying groups of islands ; 

 3. Providence island and Reef, still farther north; I. Amirante 

 Islands, a further northward step in the direction of (5) the 

 Seychelles. 



The physical relations of these different localities and their coasts 

 are ahly described in Dr. Coppinger's ' Cruise of the Alert '; I have 

 added to my descriptions of the species notes as to localities and 

 nature of bottom, taken from his own notes accompanying the 

 specimens. 



Depth. — It will be seen that the depths investigated did not 

 exceed 24 fms. 



Locality. — About half the gatherings are from a bottom composed 

 either of sand, sand and coral, or broken coral ; in but two cases (in the 

 Amirante Islands) is mud recorded ; the remaining localities are given 

 either " beach," reef, or " between tide-marks." I know of no previous 

 descriptions of Sponges from Mozambique or any part of the Eastern 

 coast of Africa nearer than Zanzibar, whence A. Hyatt* derived many 

 of theCeratose species referred to in his paper "Revision of the North- 

 American Poriferee " &c. Prof. E. P. Wright has introduced us to 

 the Sponges of the Seychelle Islands in a paper f on Alemo sei/chel- 

 lensis, collected with many other species by himself many years since. 

 The Glorioso and Amirante Islands and Providence Iteef and Island 

 are entirely new ground in this respect. Practically the only ac- 

 quaintance we have hitherto had with the Sponge-fauna of this 

 Western part of the Indian Ocean is derived from papers by Mr. Carter 

 describing a few Silicea from Mauritius (especially in Ann. & Mag. 

 Nat. Hist. 1879, iii. p. 284, five species), and one by Schuffner 

 (' Jenaische Zeitschrift/ xi. p. 403, pis. xxiv.-xxvi.) describing 6 new 

 Calcarea from Mobius's collections at Mauritius. Thus it mayjustly 

 be claimed that in magnitude and interest the present collection far 

 excels any collection hitherto described from these waters. 



Looking generally at the distribution of the fifty-six species here 

 described (see Table of Distribution, p. 586), and comparing it with 

 that of the species obtained at or near the eastern confines of the 

 same Ocean (this Report, Part I. p. 372), we find a similar resem- 

 blance to the Atlantic fauna (including the Mediterranean) in both 

 areas : excluding doubtful cases we have here 7 out of 55 species as 

 against 12 out of 106 species decidedly identical with Atlantic forms. 

 We have the same number (3) of species recorded also from Ceylon. 

 Some species (Iotrochota purpurea, ClatTiria frondifera) range to the 

 Straits of Malacca, and hence, as we have seen above (p. 371), to 

 Australia : two extend across into mid-Pacific (Oarterispongia 

 ptahitica, SteUetta acervus). The almost cosmopolitan Australian 

 species Leucetta primicjenia and Tedania digitata are found here 

 also. 



Passing,- to the more direct relations of the Australian and Western 



'D 



* Mem. Bost. Soc. ii. pt. 4, nos. ii. & v. 



t Proc. R. Irish Academy, xxviii. p. 13, pi. i. 



