12^ 'ENDEAVOUK" SCIENTIFIC KESULTS. 



spaces between the "columns" are occupied by a pro- 

 fusion of single spicules, spicule bundles, short 

 spicule strands and sheet-like patches, as well as by 

 scattered spirasters : all of which together constitute 

 no inconsiderable proportion of the entire skeleton, 

 and in macroscopic examination mask from view the 

 more definitely fibrous aggregations of the spicules. 



Spicules. 



(i.) The megascleres are tylostyli which, as a rule, are 

 straight ; they are of uniform diameter throughout 

 the greater part of their length and gradually taper 

 thence to a sharp point; greatest size 560 x 13 /<. 



(ii.) The spirasters are of a single kind and reach a length 

 of 50 }i (though usually much shorter) and a dia- 

 meter, exclusive of spines, of 5 to to ji. The spines 

 are large, approximating in length to the diameter of 

 the spicule-shaft, and in the case of the larger spic- 

 ules are about twenty in number. 



Loc. — North coast of New South Wales, eight miles east of 

 Sandon Bluffs, 35-40 fms. ("Endeavour"). 



Spirastrella alcvomoides, sp. uov. 



(Plate xxi., Wg. 2, and fig. 23.) 



Sponge cm erect, compact, sessile cluster of frondiform 

 or of angular or only slightly compressed digiiiform up- 

 growths, of which some proceed from the very base of the 

 sponge, whilst some arise as outgrowths or lobes jrom 

 others. Oscula situated apically on the digitiform ter- 

 minals. Surface smooth, with slight longitudinal in- 

 equalities and a few small asceridant papilliform projec- 

 tions. Sponge in the dry state very hard. Skeleton 

 semi-diffuse ; without fibres, but ivith occasional very 

 broad columns of parallely-arranged spicules. The sub- 

 stance of the sponge is abundantly traversed by bro7vnish 

 spongin-like streaks which, however, show no particular 

 relation to the spicule arrangement. Spirasters of a 

 single kind are plentifully scattered through all parts and 

 form a compact superficial layer. Spicules : — Tylostyli of 

 one kind, ivith blunt rounded distal extremity, measuring 

 440 X 8 ji : and large-spined stout spirasters, 40 x 7 j<. 



Two specimens of this species were obtained, both of which 

 are preserved in a dry state. The characteristic form of the 

 sponge appears to result from the upgrowth, in the first place, 

 of a few processes from a basal disk of limited extent, which 

 processes, as they grow, either remain simply digitiform. 



