REPORT ON THE MONAXONIDA. 2S 



Pachyclialina megalorrhaphis, Ridley and Dendy (PI. V. fig. G). 



1886. Pachyclialina megalorrhapliis, Ridley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, voL 



xviii. p. 328. 



Sponge (PL V. fig. 6) composed of rather slender, long, cylindrical branches, which 

 may anastomose. Maximum diameter of branches in the single specimen nearly 1 2 mm. , 

 but average diameter much less. Colour in spirit pale yellow. Texture compressible 

 and elastic. Surface almost quite smooth, very minutely hispid. Dermal membrane 

 thin, transparent, allowing the subdermal cavities to appear through it, and give to the 

 surface a faintly mottled or reticulate appearance. Oscula rather small, subuniserially 

 arranged along the branches. 



Skeleton. — (a) Dermal; not very distinct. A small-meshed reticulation of loose 

 spiculo-fibre, echinated at the nodes Ijy small tufts of projecting spicules which are the 

 ends of the primary fibres, (h) Main ; a subrectangular reticulation of spiculo-fibre and 

 single spicules, with very distinct primary lines running vertically to the surface. The 

 skeleton fibre is fairly strong and polyspiculous, but with no distinct sheath of spongirt 

 surrounding it. The main lines are five or six sjjicules broad. 



Spicules. — Slightly curved, gradually sharp-pointed oxea; size about 0'245 by 

 0-016 mm. 



The spicules of this species are large for a Chalinine sponge, and the amount of 

 spongin is correspondingly small, but the elastic, fibrous texture, the external form, and 

 the arrangement of the skeleton leave no doubt as to its systematic position. 



Zoca%.— Station 163d, June 12, 1874 ; lat. 33° 57' 30" S., long. 151° 39' 15" E. ; off 

 the coast of New South Wales ; depth, 120 fathoms ; bottom, green sand. One specimen. 



Pachychalijia elongata, Ridley and Dendy (PI. VI. fig. 1). 



1886. Pachychalina elongata, Ridley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, vol. xviii. 



p. 329. 



Sponge (PI. VI. fig. 1) digitate, ramose ; branches very long, varying in diameter ia 

 different parts of their length, up to about 12 mm., which is, however, unusually wide, 

 the average being about 8 mm. Greatest length about 300 mm. Branches sometimes 

 anastomosing. Colour (?) (now dark reddish-brown, but this is probably due to packing 

 in a metal case). Texture very compressible, elastic, tough and fibrous. Surface smooth, 

 subglabrous. The dermal membrane, together with its supporting skeleton reticulation, 

 forms a very tough, distinct skin, but very firmly adherent to the deeper portion of 

 the sponge which it encloses. Oscula small, scattered, chiefly on one side of the sponge. 



Skeleton. — (a) Dermal ; a close-meshed reticulation of stout, compact, spiculo-fibre, 

 echinated by projecting spicules; meshes small, only about O'll mm. wide, {h) Main; 

 a rectangularly meshed reticulation of spiculo-fibre, very well developed, with a great 



