Sponges from South Australia. 115 



spicules held together by a minimum of sarcode, contrasting 

 strongly, by its whiteness, with the brown translucent colour 

 of the superincumbent dermis, and constituting the chief sup- 

 porting element of the branches. Spicules of two forms, both 

 skeletal, no flesh-spicules, viz.: — 1, acuate, simple, smooth, 

 curved, abruptly sharp-pointed, 75 by 2-6000ths in. in its 

 greatest dimensions (tig. 6, a) ; 2, acerate, smooth, curved, 

 rather flexuous, gradually sharp-pointed, a little longer than 

 No. 1 (fig. 6, b) ; apparently modifications of each other, 

 as specimens of all sizes and transilionary forms may be found 

 among them ; equally and plentifully distributed throughout 

 the dermis ; forming in bundles the axes of the thorn-like 

 projections, and constituting, as before stated, the chief in- 

 durating element of the stem and branches. Size of specimen 

 16 in. high by 16 x 2\ in. horizontally. 

 Iiab. Marine. 



Loc. Port Phillip Heads, S. Australia. Depth 19 fath. 

 Obs. This genus was established by Schmidt in 1862 for 

 two species found in the Adriatic (' Die Spong. d. Adriatisch. 

 Meeres,' p. 64, Taf. vi. fig. 7 &c), in which the acuate is long 

 and very flexuous or undulatory, while that of the Australian 

 species is comparatively short and simply curved ; otherwise 

 there is not much difference between the two species, so little 

 indeed that I am in doubt whether the above-described ought 

 not to be termed a " variety." The specimen has been depo- 

 sited in the British Museum, where it bears the Register no. 

 " 84. 10. 10. 2." 



Compactness and hardness of the stem are peculiarly cha- 

 racteristic of my order Echinonemata, arising from condensa- 

 tion of the spicular element of the sponge in these parts. 



Chalina polyclwtoma, var. trichotoma, n. v. 



Specimen dry. Solid, caulescent, digitations long, round 

 and dichotomously branching at first, then ending in expanded, 

 compressed extremities, more or less trichotomously divided, 

 all arising from a single, short, round stem. Consistence 

 resilient. Colour now light sponge. Surface uniformly even, 

 covered with dermal sarcode, corresponding in its reticulation 

 with the subjacent fibres on which it rests. Pores in the 

 interstices of the reticulation. Vents in line along the 

 branches, or scattered over one side especially of the expanded 

 extremities. Internally, structure open, fibro-reticulated, 

 smaller, firmer, and more compact on the surface. Spicule of 

 one form only, viz. acerate, curved, smooth, fusiform, sharp- 

 pointed, very minute and thin, about 8-6000ths in. in length, 

 chiefly confined to a line running through the centre of the 



