2 Dr. G. J. Ilinde on some new 



Uruguaya repe7is, n. sp. (PI. IV. figs. 1-6.) 



Sponge incrusting, growing evenly over a continuous sur- 

 face of a fragment of wood. Colour in the dry state of a light 

 lead-brown, both on the surface and in the interior of the 

 sponge. Skeleton very hard and resistant. Surface smooth 

 and even, with numerous minute irregular apertures, scarcely 

 visible without a lens. Neither canals nor oscules are shown 

 in the skeleton. This is built up of large, slightly arcuate, 

 smooth, cylindrical spicules, evenly rounded at both ends, 

 which are so disposed as to form an open meshwork with loop- 

 like interspaces. The spicules of the surface-layer are much 

 more closely arranged than those of the interior. The gem- 

 raulcs occur either singly or in small groups or monticules, 

 which are attached to the surface of the wood overgrown by the 

 sponge and enclosed by a spicular envelope or layer, the spi- 

 cules of which are of the same form, but usually smaller than 

 those of the skeleton. The gemraules are subglobate in form 

 and covered by a single layer of amphidisc-spicules with 

 smooth incurved complete margins and stout shafts, which 

 slightly project beyond the rotules at both ends. 



The specimen partially covers an irregularly-shaped frac- 

 tured fragment of decaying wood with a smooth crust, about 

 1 millim. in tliickness, which is nearly of the same tint in its 

 dried state as the wood itself. Evidently the sponge ori- 

 ginally incrusted nearly the entire piece, for here and there 

 small monticules of gemmules yet remain on the exposed 

 surfaces, which must have been formed when these were 

 covered by the sponge. The smooth even surface of the 

 sponge has a punctate appearance, produced by minute 

 rounded or subpolygonal apertures, varying from "13 to '4 

 millim. in width, which open into the interior of the mesh. 

 The skeleton-spicules are all curved to a slightly varying 

 degree and uniformly cylindrical ; they are smooth, but under 

 high powers of the microscope a slight micropunctation is 

 apparent near the rounded ends. They vary from '15 to "24 

 millim. in length and from "02 to "03 millim. in thickness. 

 The spicules are grouped as it were in fascicles, to form the 

 mesh J those of the same fascicle are nearly parallel with each 

 other, and project from a common centre. The surface-layer 

 in some patches is completely felted over with spicules. 



The gemmules are invariably attached to the surface of the 

 wood on which the sponge is growing, and in no instance do 

 they appear to be imbedded in the skeleton tissue of the 

 sponge. On lifting up a portion of the sponge from the sur- 

 face of the wood they always remain behind, fixed to the 



