1887.] NATURAL SCIENCES OF PHILADELPHIA. 249 



Sponge "thin, encrusting. Surface even. Structure fragile, 

 crumbling. Color now brown. Skeleton spicule curved, fusiform, 

 abruptly sharp-pointed, spiniferous or smooth. Statoblast globular; 

 aperture sunken, infundibular ; crust composed of granular micro- 

 cell structure, charged with two kinds of injequibirotulates, one 

 form of which is much stouter than the other, and consists of a 

 straight shaft passing by trumpet-like expansion into the large 

 disk, which often has radiating lines, and abruptly terminating in. 

 the other, which is only one fourth the diameter of the former ; the 

 other form similarly constucted, but more delicate, with the shaft 

 inflated towards the large disk, and the smaller one much less in 

 proportion than in the larger form ; the forms not mixed but con- 

 fined to their statoblasts respectively ; arranged perpendicularly, 

 with the large disk resting on the chitinous coat, and the smaller 

 one forming part of the surface of the statoblast." Carter. 



Loc. River Amazon. 



(2) Tubella spinata, Carter. Ann. and Mag. 1881, p. 96. 



Sponge "thin, coating, spreading. Structure fragile, crumbling. 

 Color light brown. Skeleton spicule curved, fusiform, gradually 

 sharp-pointed, smooth or spiniferous. Flesh spicule minute, curved, 

 usiform, thin, gradually sharp-pointed, covered with perpendicular 

 spines, which are longest about the centre. Statoblast elliptical, 

 flask-shaped ; aperture terminal ; crust thick, composed of granular 

 microcell-substance charged with insequibirotulate spicules consist- 

 ing of a straight shaft inflated near the small end, and passing by a 

 trumpet-like expansion into the large disk. Sparsely spined ; disk 

 circular, smooth, with an even margin, small end consisting of a 

 circular convex head, regularly denticulated on the margin with 

 eight or more conical processes, which are slightly inclined towards 

 the shaft ; arranged perpendicularly, so that the disk rests on the 

 chitinous coat and the head forms part of the surface of the stato- 

 blast." Carter. 



Loc. River Amazon. 



(3) Tubella reticulata, Carter. Ann. and Mag. 1881, p. 97. 



Spongilla reticulata, Bowerbank. Proc. Zool. Soc. etc. 1863, p. 

 455. 



Sponge "elliptical, or fusiform when growing round the immersed 

 small branches of trees. Structure extremely rigid, reticulate, ter- 

 minating in thorn-like processes on the surface. Color light sea- 

 green when growing in clear water. Skeleton spicules curved or 

 17 



