Sponges from South Australia. 53 



to it ; holes in the cloaca numerous, variable in size and distance 

 apart in proportion to the breadth of the intervening skeletal 

 structure of this cavity ; subcircular and presenting within 

 respectively from one to four openings which belong to the 

 structure of the wall. Structure of the wall like that of the 

 foregoing species of Heteropia. Spicules of two kinds, viz. 

 acerate and triradiate ; no quadriradiates : — 1, acerates of 

 two forms, viz. one long, straight, thin, and cylindrical, and 

 the other slightly curved, stouter, and fusiform, the latter 

 varying in size under 255 by 9-6000ths in.; 2, triradiates, 

 small and large, the latter far exceeding the others in size, 

 averaging 85 by 5-6000ths in. in the shaft, with arms 

 30 by 5-6000ths in. No. 1 in its thinner form is con- 

 fined to the peristome, and in its stouter one echinates the 

 surface generally, where its inner part, which is most attenu- 

 ated, is deeply sunk into the wall, and its outer part, which 

 is thicker, curved towards the plurality of mouths respec- 

 tively ; no. 2 in its smaller and more regular form is chiefly 

 confined to the skeletal structure of the surface and cloaca, 

 and the larger ones to the interior, where their straight 

 long shafts, coming from opposite sides of the wall, over- 

 lap each other, as in the foregoing species. I saw neither 

 quadriradiates nor mortar-spicules. Size of specimen about 

 4-12ths in. high by 7-12ths horizontally in its greatest 

 diameter. 



26. Heteropia erecta. 



Agglomerate. Specimen erect, compressed, contracted 

 towards the point of attachment, consisting of several indi- 

 viduals of different sizes sprouting out obliquely upwards 

 from the general mass in conical forms, each provided 

 with a peristome. Colour whitish yellow outside, sponge- 

 brown within. Surface even, uniformly composed of mode- 

 rately large triradiates, held in position by cribriform 

 sarcode. Pores in more or less defined areas of the cri- 

 briform sarcode, bounded by the intercrossing arms of the 

 dermal triradiates ; large generally, but presenting two 

 sizes, viz. one the most numerous, about l-8oOtli in. in 

 diameter, and the other about l-276th in., the latter scat- 

 tered irregularly amongst the former. Vents single and 

 terminal, at the ends of the conical individuals respectively, 

 each furnished with a peristome, leading after a short 

 distance from a narrow cavity in each conical portion to a 

 general one much wider than the walls of the former, which 

 are about l-24th in. thick; holes in the cloaca very variable 

 in size and distance apart, the latter corresponding in width 



