96 RECORDS OF THE AUSTRALIAN MUSEUM. 



consists of flabellate expansions, more or less semicircular in out- 

 line, with several points of attachment along the base, and 

 frequently there are one or more vertical lamellte placed at right 

 angles to the main frond. The height is usually about equal to 

 the breadth ; the basal portion measures from 20 to 30 mm. in 

 thickness, at the distal fourth the lamina gradually decreases in 

 diameter and the upper margin is subacute. The surface bears 

 numerous conuli, from 1 to 6 mm. high, the average being about 

 5 mm. ; they are arranged in circles, and surround the funnel- 

 shaped inhalent pores; the raised margins of the latter, with the 

 conuli, form elevated longitudinal or subradiate ridges about 5 mm. 

 wide. The pores are from 1 to 2*5 mm. in diameter. The spaces 

 between the ridges are occupied by grooves 4 mm. in width ; they 

 are generally well developed near the distal margin, but frequently 

 they are continuous from the base to the summit; in transverse 

 section they form half or two-thirds of a circle; in many cases 

 they are tubular at their origin, but rarely circular at their ter- 

 mination. In the massive lobose forms there are numerous 

 scattered oscula on the sides of the lamellse, but they are more 

 abundant on the margins no matter what the shape may be, 

 their diameter varies from 3 to 8 mm. Texture in the dry state 

 very hard and scarcely compressible between the fingers ; when 

 wet, moderately soft, very tough, and highly elastic. This variety 

 would be useful for any purpose requiring a firm, tough, durable 

 sponge. Colour varying from dark yellowish- to purplish-brown. 



Skeleton. — The arrangement of the fibres and their diameter 

 agrees with the description ; they are remarkable for their uni- 

 formity in thickness. The foreign spicules in the spirit specimen 

 and also in all the others examined, are never so numerous as to form 

 "a dense axial column"; they are generally two or three in a row 

 and are very scarce in the central parts of the sponge, becoming 

 more frequent as the surface is approached. The fibres of the 

 conuli have an axial core, consisting of one or two rows of foreign 

 spicules, and in well preserved specimens numerous spicules occur 

 outside the fibres. 



EUSPONGIA IRREGULARIS, Var. AREOLATA, VaV. nOV. 



(Plate xii., fig. 18). 

 Sponge usually consisting of a main semicircular flabellate 

 lamina, which gives off at right angles from one to four or more 

 short lateral leaflets ; the latter rarely reach to the upper margin 

 of the main frond. The main lamina is usually about 25 mm. in 

 thickness at the base; the average thickness is about 10 mm. The 

 apical margins are subacute and 5 mm. in diameter. The upper 

 semicircular margin presents a few large circular oscula, ranging 

 from 5 to 20 mm. in diameter. On the external surface their 

 course is more or less marked on each side by prominent rounded 

 longitudinal ridges, and the apical external diameter of the elevated 



