Sjjecies o/" Uruguaja, Carter. 7 



base. The surface in the dry state is of a lead-grey tint with 

 a smooth shiny aspect, the interior is of a lighter tint. It 

 is very hard and resistant in texture. The branches are com- 

 pressed; they frequently coalesce into semipalraate expan- 

 sions. The oscules are for the most part simple, circular, or 

 elliptical, scarcely if at all elevated above the general surface ; 

 they are usually ranged in vertical rows along the thin com- 

 pressed edges of the branches. The general surface shows 

 the minute irregular apertures between the spicular mesh as 

 in the species already described. The spicules are cylin- 

 drical -with rounded extremities, unusually robust ; their 

 surfaces are faintly micropunctate. No gemmales have as 

 yet been met with in this species. 



The type specimen, on which Dr. Bowerbank based his 

 excellent description of this species, is about 225 millim, in 

 height, 175 millim. in width, and from 50 to 75 millim. in 

 thickness. The basal portion has been broken from the 

 surface to which it was attached ; but there are smooth patches 

 on its underside covered by membrane, where the sponge 

 apparently rested on a rock or pebbly surface. The oscules 

 are from 1 to 2 millim. apart and about "75 millim. in dia- 

 meter ; they have a well-defined border of closely arranged 

 spicules. As in U. Maccmdreivi, the spicules of the surface 

 are much more closely arranged than in the interior and form a 

 definite crust to the sponge. 



The skeleton-spicules average '28 millim. in length by 

 •052 millim. in thickness. A few acerate spicules are 

 mingled with the cylindrical forms ; they are evidently, as 

 Dr. Bowerbank has remarked, only immature forms, and this 

 is further proved by the fact that within some of the cylindrical 

 spicules the outlines of acerate spicules can still be distin- 

 guished. The micropunctation of the spicules can be seen 

 only under high powers of the microscope. 



I have made a careful search for gemmules in the type 

 specimen of this species now preserved in the museum of the 

 Koyal College of Surgeons, but failed to find any. In some 

 of the membranous patches on the underside of the sponge, 

 where it had been resting on the pebbly or rocky floor of the 

 stream, there w^ere enclosed a few small capsular bodies com- 

 posed of minute cylindrical spicules, not dissimilar to those of 

 the monticular envelope of U. Macandreivi. There were, 

 however, no traces of gemmules within them, and I there- 

 fore conclude that they may have been young individuals of 

 U. pygmcea, described below, which had been overgrown by 

 the larger sponge. 



At my request Mr, T. Higgin, F.L.S., examined the fine 



