Report on the zoological collections made in the Indo-Pacific Ocean ...

SPONGHDA. 583representing the African coast) ; 2. Glorioso Islands (as the mostsouthern investigated member of the outlying groups of islands ;3. Providence Island and lleef, still further north ; 4. AmiranteIslands, a further northward step in the direction of (5) theSej'chelles.The physical relations of these different localities and their coastsare ably described in Dr. Coppinger's Cruise of the Alert ' '; I haveadded to my descriptions of the species notes as to localities andnature of bottom, taken from his own notes accompanying thespecimens.Depth.—It will be seen that the depths investigated did notexceed 24 fms.Localltij.—Ahoni half the gatherings are from a bottom composedeither of sand, sand and coral, or broken coral ; in but two cases (in theAmirante Islands) is mud recorded ; the remaining localities are giveneither " beach," reef, or " between tide-marks." I know of no previousdescriptions of Sponges from Mozambicjue or any part of the Easterncoast of Africa nearer than Zanzibar, whence A. Hyatt* derived manyof theCeratose species referred to in his paper "Hevision of the North-American Poriferaj " &c. Prof. E. P. Wright has introduced us tothe Sponges of the Seychelle Islands in a paper t on Alemo seycJiellensis,collected with many other species by himself many years since.The Glorioso and Amirante Islands and Providence Reef and Islandare entirely new ground in this respect. Practically the only acquaintancewe have hitherto had with the Sponge-fauna of thisWestern part of the Indian Ocean is derived from papers by Mr. Carterdescribing a few Silicea from Mauritius (especially in Ann. & jMag.Nat. Hist. 1879, iii. p. 284, five species), and one by Schuffner(' Jenaische Zeitschrift,' xi. p. 403, pis. xxiv.-xxvi.) describing (5 newCalcarea from Mcibius's collections at Mauritius. Thus it may justlybe claimed that in magnitude and interest the present collection farexcels any collection hitherto described from these waters.Looking generally at the distribution of the fifty-six species heredescribed (see Table of Distribution, p. 586), and comparing it withthat of the species obtained at or near the eastern confines of thesame Ocean (this <strong>Report</strong>, Part I. p. 372), we find a similar resemblanceto the Atlantic fauna (including the Mediterranean) in bothareas : excluding doubtful cases we have here 7 out of 55 species asagainst 12 out of 106 species decidedly identical with Atlantic forms.We have the same number (3) of species recorded also from Ceylon.Some species (lotrochota purpurea, Clafhria frondifera) range to theStraits of Malacca, and hence, as we have seen above (p. 371), toAustralia; two extend across into mid-Pacific (Carterisjioiu/iaotahitica, StelJetta acervus). The almost cosmopolitan Australianspecies Leucetta primvjenia and Tedania digitata are found heroalso.Passing to the more direct relations of the Australian and Western* Mem. Bost. Soc. ii. pt. 4, nos. ii. & v.t Proc. R. Irish Academy, xxviii. p. 13, pi. i.