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Show 1906.] OF THE THIRD TANGANYIKA EXPEDITION. 219 from the Ugalla River, a tributary of the Malagarassi River flowing into the lake, viz. S. bohmii Hilgendorf and S. nitens Carter. The number of known species of African Freshwater Sponges is thus brought up to 19. The following is a list of the species referred to in this paper:- Spongilla carteri Bowerbank. Victoria Nyanza. Spongilla moorei Evans. Tanganyika. Spongilla tanganyikce Evans. Tanganyika. Spongilla cunningtoni, sp. n. Tanganyika. Spongilla biseriata Weltner. Nyasa. Spongilla rousseletii, sp. n. Victoria Falls, Zambesi. Spongilla ? zambesiana, sp. n. Victoria Falls, Zambesi. Ephydatia plumosa Carter var. brouni, nov. var. White Nile. SPONGILLA CARTERI Bowerbank. (Plate XV. figs. 1-4.) 1848. Spongilla friabilis Lamarck, Carter, Ann. Mag. N. H. (2) i. p. 310; 1849. Carter, ibid. (2) iv. p. 81. 1863. Spongilla carteri Bowerbank, Proc. Zool. Soc. 1863, p. 469. 1887. Spongilla carteri Potts, Proc. Acad. N. S. Philadelphia, 1887, p. 194. There are two small specimens of this species, one of which has been removed from a piece of rock, the other from a shell of Aetheria. Unfortunately there are no gemmules present, but the characters of the surface and of the skeletal framework are those of Bowerbank's species. Plate X V . figs. 2, 3, 4 represent the oxeas * of specimens from the Victoria Nyanza, Bombay, and Mauritius respectively ; it will be seen that the first (258 x 9'5 p) is the smallest and has abruptly pointed almost tornote ends. The average size of the oxeas of the type specimen from Bombay is 287 x 11*75 u and of the Mauritius specimen 349 x 18'5 u. The thin dermal membrane, perforated by groups of pores, stretches between the sharp-pointed irregular conules formed by the ends of the longitudinal main fibres. Localities.- -Entebbe, Victoria Nyanza, shallow water. Bombay; Mauritius ; Calcutta ; Madura I. ; N. Java ; Lake Balaton, Hungary. SPONGILLA MOOREI Evans. (Plate XV. figs. 5-9.) 1899. Spongilla moorei Evans, Quart. Journ. Micr. Sci. vol. xii. p. 472, pi. xxxvii. figs. 1-5, and pi. xxxviii. figs. 6-8. There are five specimens of this species from five localities in Lake Tanganyika : three come from shallow water, and two from about 10 fathoms. They are all in the form of thin crusts from | to 1| m m . thick on stones and shells, and none of them attains * The terms " oxea," " tornote,''" "strongyle," clearly defined by Sollas in 1888 (' Challenger 'Rep. Tetractinellida, pp. liv, Iv), seem to m e preferable to " amphioxea," &z., because, in addition to having claim-! of priority and brevity, they leave no doabt as to the form of the spicules they are intended to designate. |