Sponges from South Australia. 49 



22. Heteropia patuhscuUfera. 



Agglomerated. Specimen consisting of a large bunch of 

 inflated sac-like individuals of different sizes irregularly grow- 

 ing out of each other, more or less conical, and opening re- 

 spectively by, for the most part, large mouths indistinctly 

 peristomed. Colour whitish yellow outside, sponge-brown 

 within. Surface consisting of cribriform sarcode without 

 mortar-spicules, knitting together triradiates, both regular and 

 irregular, of tolerably uniform size, which is rather small ; 

 echinated, especially towards the mouth, with large, curved, 

 fusiform acerates, sublanciform at the free end. Pores, the 

 holes of the cribriform sarcode, small and large mixed, the 

 latter about l-280th in. in diameter. Vents single, terminal, 

 more or less large as the free end of the individual is more or 

 less conical, each provided with a short peristome, and all 

 leading to a more or less general cavity which is rendered 

 irregular in form by its branch-like extensions into the diffe- 

 rent individuals of the mass ; far exceeding in size the thick- 

 ness of the wall, which is thus reduced to a mere shell-like 

 thinness ; holes in the cloaca numerous, tolerably uniform in 

 size and distance apart, each presenting one or more sphinc- 

 tered apertures under the common level of the cloacal layer ; 

 these belong to the wall-structure, and thus simulate sub- 

 cloacal cavities. Wall very thin, as before stated, compared with 

 the bulk of the individual and the largely dilated cloacal cavity, 

 about l-40th in. in diameter, consisting of empty sinuous 

 canals in juxtaposition, intercommunicating by pores and 

 large holes respectively, the latter giving it a clathrous ap- 

 pearance ; " holes " of intercommunication larger immediately 

 under the pores of the dermis, simulating " subdermal cavi- 

 ties," and the same under the cloaca ; skeletal structure chiefly 

 composed of large triradiate spicules with long shafts, whose 

 sagittal heads support the cortex on one side and the cloaca on 

 the other, while their shafts more or less overlap each other 

 horizontally in the intervening space. Spicules of three 

 kinds, viz. acerate, triradiate, and quadriradiate : — 1, acerates 

 of two forms, viz. one thin, long, straight, cylindrical, simi- 

 larly pointed at each end, and the other thick, curved, fusi- 

 form, and lanceolate at the free end, measuring about 140 by 

 10-6000ths in. ; 2, triradiates of different sizes, large and 

 small, regular and irregular, the largest sagittal much exceed- 

 ing the rest in dimensions, being about 90 by 6-6000ths in. 

 in the shaft, with arms respectively about half this length ; 3, 

 quadriradiates, similar in size in their triradiate portion to the 

 small triradiates, with the addition, of course, of the fourth 

 arm. No. 1, in its finer form, is confined to the peristome, 



Ann. & Mag. N. Hist. Ser. 5. Vol. xviii. 4 



