BY E. F. KALLMANN. 301 



Spicules. - The tylostyli are straight or nearly so, gradually 

 sharp-pointed, and of approximately uniform diameter throughout 

 more than three-fourths of their length; are usually provided 

 with a phyma of moderately large size, which is of very variable 

 shape, and is frequently asymmetrical and misshapen ; and 

 measure from 330 to 450 /x in length by 12-5 /ut, at most, in 

 diameter. Styli, of similar dimensions, occur, but are compara- 

 tively rare. The microscleres are of three kinds: (i.) spirasters 

 of variable form; frequently with a straight or nearly straight 

 axis; with usually more or less radially disposed, not numerous, 

 spines, the length of which is not greater than the diameter of 

 the spicule; rarely more than 30 jx long; and in different speci- 

 mens varying in maximum diameter from 5 to 7 /x, exclusive of 

 spines. (ii.) Minutely and closely spined, generally straight, 

 truncately-ended rods; 7 to 19 /x in length; and seldom more 

 than 3/x in diameter, inclusive of spines. (iii.) Sharp-pointed 

 slender acanthoxea; with a not very pronounced, elongate, median, 

 spiral flexure of usually less than one complete turn ; with 

 linearly and usually spirally arranged, sharp, slender spines, the 

 length of which sometimes exceeds the diameter of the spicules; 

 varying in length from 55 to 110/x; and rarely more than 2*5 /x 

 in diameter. 



Log. — Port Jackson. 



Remarks. — I regard this species, provisionally, as belonging to 

 a subgenus of Clio7ia, having as its type Papillissa lutea Lendf,, 

 and including Spirastrella areolata Dendy(l^). 



Very closely allied to Cliona hixonii— sXthow^h to be regarded, 

 I think, as a quite distinct species - is another large sponge from 

 Port Jackson (represented in the Australian Museum by a single 

 specimen), in which (PI. xvi., figs.3, 4), instead of a simple areola- 

 tion of the surface, there are low papillae of very uniform size, 

 shape, and distribution, and more widely separated from one 

 another than the areolae of C. hixonii; and in which, also, the 

 microscleres corresponding to those termed by me spirasters in 

 the above description, are comparatively short and stout, and 

 provided with close-set, fairly large spines that often show a 

 tendency to assume a whorled arrangement. 



