REPORT ON THE MONAXONIDA. 185 



Skeleton. — There is an extremely irregular reticulation of scattered spicules, amongst 

 which one can distinguish rather loose, plumose fibres, running more or less vertically 

 towards the surface. 



Spicules.— Megasclera ; (l) rather short and stout, smooth, slightly curved styli ; 

 usually with a bend towards the base ; sharply and fairly gradually pointed at the apex ; 

 size about 0"45 by 0'02 mm. (2) Smooth, curved oxea, sharply and fairly gradually 

 pointed ; of about the same size as the styli ; scarce. 



The most characteristic feature of this sponge is the glabrous, reticulate dermal 

 membrane ; the reticulate a^^pearance is not caused by the presence of a reticulate 

 dermal skeleton but by a network of thicker, faintly fibrous-looking tissue in the dermal 

 membrane itself 



The species is further distinguished within its genus by its large, prominent oscula. 



Locality. — Bahia ; depth, 7 to 20 fathoms. One specimen. 



Axinella monticularis, Eidley and Dendy (PI. XXXVIII. fig. 5). 



1886. Axinella monticularis^ Ridley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, voL xviii. 



p. 481. 



Sponge (PL XXXVIII. fig. 5) massive, subglobular, sessile, but apparently free. The 

 largest specimen measures 44 by 31 by 21 mm. Colour in spirit yellowish -grey. 

 Texture finn and compact, very gritty owing to the presence of a large quantity of 

 calcareous foreign matter {e.g., Foraminifera) within the sponge. Some of the foreign 

 bodies are large and others small, but all become completely enveloped by the sponge. 

 Surface thickly covered with very numerous, sharp, prominent but small conuli, 

 averaging about 1'5 mm. in height, which give to the specimens a very characteristic 

 appearance. Over and between the conuli the surface is glabrous, yet it is in parts very 

 minutely hispid. 



Skeleton. — There is no dermal reticulation. The numerous foreign bodies in the 

 sponge are echinated by the spicules and many of them also form an origin for stout 

 columns of typical Axinellid spiculo-fibre. The skeleton columns are well developed 

 and run vertically to the surface, ending in the conuli above mentioned. They are 

 composed of stylote spicules of various sizes, some smooth and some (of the smaller ones) 

 spined ; the spicules have their bases towards the centre of the fibre and their apices 

 projecting freely outwards and forwards in a plume-like fashion. Normally all the 

 spicules appear to have some definite base, either in the fibre, where each one is 

 supported by the rest, or on some foreign body ; but a few may be observed loosely 

 scattered between the fibres. 



Spicules. — Megasclera; styU, of two distinct kinds. (1) Smooth, usually slightly 

 1 lent towards the base, very gradually and sharply pointed (tapering from base to apex) ; 



(ZOOL. CHALL EXP. — PART LIS. — 1887.) Nnn 24 



