146 U.S. NATIONAL MUSEUM BULLETIN 272 



Gemmules comparatively few in number, subspherical, diameter 

 ranging 480-600 fi; restricted to base of sponge, firmly adhering sub- 

 stratum, occurring in groups of 2-5, surrounded by a strong capsule 

 of typical but smaller megascleres; pneumatic coat apparently a solid 

 mass of spongin; gemmoscleres embedded in this coat in one layer, 

 their inner rotules overlapping; foramen not reliably determinable. 



Distribution. — Apparently known only from the type locality, 

 "Paraguay." 



Color in life. — Not yet observed; dry sponge almost black in 

 upper parts, lighter in its interior. 



Discussion. — With our present insufficient knowledge of members 

 of this genus, the relationship of the species discussed cannot be 

 reliably ascertained. From U. corallioides it seems only to differ by 

 its microgranulated and somewhat slimmer megascleres, the other 

 known criteria of both are almost identical. Additional studies, and in 

 particular collections in South American waters, are of utmost 

 importance. 



Uruguaya repens Hinde, 1888 



Plate 13, figure 5 



Uruguaya repens Hinde, 1888, p. 2. — Weltner, 1895, p. 114. — Gee, 1931e, p. 47; 

 1932c, p. 44.— Cordero, 1925, p. 117 (key) .—Penney, 1960, p. 61. 



Material. — Slide of syntype (N. Gist Gee no. 54827) . 



Description. — Sponge, according to Hinde (1888), forming flat 

 encrustations without branches; surface smooth and even. Skeleton 

 rigid and hard. 



Megascleres used for the skeleton of only one class, i.e., stout, 

 moderately curved, cylindrical, and entirely smooth amphistrongyla ; 

 microgranulations often present at their tips; length range 165-250 

 n, width range 24-35 n; smaller megascleres found only in the vicinity 

 of gemmules. 



Microscleres absent. 



Gemmoscleres minute birotulates with a stout, smooth, and short 

 shaft, and terminally mth equal rotules of strongly recurved circular 

 margins; length of shaft 14-15 /x, its thickness about 6 ju; diameter of 

 rotules 15-16 /x. 



Gemmules invariably attached to the substratum, subspherical, 

 diameter ranging 240-480 ju, occurring in groups from 3-5, surrounded 

 by a strong capsule of typical but smaller megascleres; pneumatic 

 coat apparently a solid mass of spongin; gemmoscleres embedded in 

 this coat in one layer, the outer rotules slightly exceeding surface of 

 pneumatic coat; foramen not reliably determinable. 



Distribution. — Apparently known only from the type locality, the 

 Uruguay R. 



