Sponges from South Australia. 457 



Trachya globosa, var. rugosa, n. var. 



This is a spherical variety with a dark grey cortex, pitted 

 uniformly all over the surface, the pits consisting of subcircular 

 depressions with raised borders in juxtaposition. Stipitate, 

 with a large, round, single vent on the summit. Spiculation 

 the same as that of the original species described in the 

 'Annals' of 1886 (vol. xvii. p. 121), viz. consisting of 

 enormously long acerates accompanied by small bihamates. 



Loc. Port Western. 



Ohs. In this variety the bihamates, on account of their 

 smallness, do not come out distinctly until a bit has been 

 dried and mounted in balsam, when they make their appear- 

 ance abundantly, together with the groups of dark pigment- 

 cells which colour the cortex, thus resembling the Tethyina 

 [T. cranium &c.) ; but there are no trifid spicules anywhere. 



Trachya horrida, n. sp. 



Massive, irregularly elliptical, elongate or bolster-shaped, 

 growing round a similarly-shaped nucleus of agglomerated 

 sandy rocks ; presenting a glistening villous surface, produced 

 by the projecting ends of the spiculation. Colour grey. Sur- 

 face uniformly even and villous. Pores not seen. Vents few 

 and not conspicuous. Internal structure very compact, con- 

 sisting of sarcode densely charged with the spicules of the 

 species. Spicules of one form only, viz. acerate, but of two 

 sizes, the largest, long, smooth, fusiform, curved, and 

 gradually narrowed to a sharp point at each end, about 750 

 by 12-6000ths in., and the other, the smallest, of the same 

 form but variable in measurement. No. 1 chiefly constitutes 

 the body-mass, where the spicules are arranged parallel to 

 each other, and, radiating from the base to the circumference, 

 become mingled there with a layer of no. 2, thus causing 

 the specimen (in a vertical section) to present a cortical 

 layer about l-18th in. thick. Size of specimen about 

 6 in. high from the base of attachment, which was at one 

 end, and 3-| x 2 in. in horizontal diameter, varying in thick- 

 ness with the irregularities of the piece of rock over which it 

 has grown, being in some parts 2 in. thick. 



Loc. Port Western. 



Ohs. Designated " horrida " on account of the disagreeable 

 manner in which the large spicules are torn away by adhering 

 to the fingers when the specimen is handled. 



