4 Dr. G. J. Hinde on some new 



A remarkable feature in connexion with U. repens is the 

 close agreement in details of form of the amphidisc-spicules 

 with those of other freshwater sponges of the genus Mei/enia, 

 Carter, which occur in widely separated geographical areas. 

 Thus, for example, the amphidisc-spicules of Meyenia Leidyi, 

 Bowbk., sp. *, from the Schuylkill River, near Philadelphia, 

 of Meyenia gregaria, Bowbk., sp. fj from the River Amazons, 

 and of Meyenia erimaceus, Ehr., sp. t, fi'om the River Elbe, 

 alike possess circular, complete, curved margins, and their 

 shafts are similarly prolonged into small bosses at both ends 

 of the spicules, so that there are, in fact, only unimportant 

 differences in the size of the amphidiscs in these species of 

 Meyenia and in Uriiguaya repens. But with this similarity 

 in the form of the amphidisc-spicules there are notable differ- 

 ences in the characters of the skeleton in the above-named 

 species of Meyenia which distinguish them from eacli other 

 and from Uruguaya. 



Distribution. River Uruguay, South America. Only a 

 single specimen has at present been discovered, and the exact 

 locaHty whence it comes is unknown to me. 



Uruguaya Macandrewi, n. sp. (PI. IV. figs. 11-14.) 



1881. Urnf/udT/a coraUioides, Carter (in part), Ann. & Mag. Nat. Plist. 

 ser. 5, vol. vii. p. 100. 



Sponge with an incrusting base, from which numerous 

 thickly-set palmate sterns or branches arise, which partially 

 coalesce and give off digitiform processes with truncated 

 summits. The exterior surface is very dark, almost black in 

 appearance, but the interior is of a much lighter tint and 

 approaches silver-grey. The surface is smooth and even and 

 in the lower portion compact. The skeleton is very hard and 

 resistant to pressure. The oscules are circular, elliptical, or 

 trifoliate in outline ; they have no regular arrangement, but 

 are scattered indiscriminately over the surface of the branches. 

 There is usually a small cavity immediately beneath the 

 oscular aperture. The canals in the interior of the sivcleton 

 can scarcely be distinguished from the interspaces of the 

 mesh. The skcleton-spicules are moderately robust, decidedly 

 arcuate, cylindrical, evenly rounded at the ends. There are 

 also a few slender acerate spicules and transitional forms 

 between these and the cylindrical spicules. The surface of 



* Proc. Zool. Soc. 1863, p. 7, pi. xxxviii. fig. 2 b. 

 t Idid, p. 34, pi. xxxviii. fig. 7 d, e. 



X See Vejdovsky, " Die Siisswasser-Scliwamme Bohmens," Abli. 

 kcinigl. Gesellsch. Wiss. (Prag), 1883, p. 31, pi. iii. figs. 11-13. 



