SPONGES. 141 



straight line from cud to end) by 0-002 milliin. (in Hi.- middle); very :ilnmd;uitly 

 distributed through the soft tissues iu association with scattered oxt-.i. 

 li.N. 109 (Gulf of Manaar. Type) ; 306 (Stat. XXIV., off Trincoinalee). 



Strongylophora, n. gen. 



Gelliinae with the skeleton composed of a reticulation of strongyla of various sizes, 

 partly collected in fibres, but with little (if any) spongin. With microscleres in 

 the form of smooth microxea, chiefly found in the dermal membrane. 

 This is n remarkable genus of somewhat doubtful systematic position. The 

 presence of the fusiform (and often angulated) dermal microxea suggests an affinity 

 with the Homosclerophora and Pachastrellidre amongst the Tetractinellida, ratlin 

 than with the Sigmatophora. We cannot, however, lay very much stress upon this 

 character when we remember the generalized character of microxea and the fact that 

 such spicules also occur in the Ectyonine genus Fusifer (vide DENDY, 10). 



Strongylophora durissima, n. sp. Plate IX., fig. 1. 



Sponge massive, irregular ; may be depressed and cake-like or subcylindrical and 

 slightly ramose. Surface very uneven, sometimes with angular grooves and ridges, 

 giving it a curious crumpled appearance ; minutely and uniformly granular. Vents 

 few, scattered ; circular and often rather large, up to about 4 millims. in diameter ; 

 each the opening of a wide cylindrical oscular tube which runs vertically inwards for 

 a considerable distance. Inhalant pores minute, abundantly scattered in the meshes 

 of the dermal reticulation. Colour (in spirit) greyish-brown throughout. Texture 

 hard and stony, but brittle, and rather cavernous internally owing to the presence of 

 the numerous canals of varying diameter. The larger of the two specimens measures 

 about 45 millims. in maximum diameter. 



The main skeleton is an irregular but fairly close-meshed and, towards the surface, 

 sub-rectangular reticulation of more or less stout spicular fibre composed of closely 

 packed strongyla, with numerous loose strongyla scattered between the fibres. The 

 dermal skeleton (Plate IX., fig. 1) is a reticulation of mostly large and single 

 strongyla ; their ends come in contact with one another, many together, at the 

 principal nodes of the reticulation, from which they radiate, and at each of these 

 nodes there is also a little heap of very short strongyla. The presence of these nodal 

 heaps gives the characteristic granular appearance to the surface of the sponge. 



Spicules. (l.) Strongyla (Plate IX., fig. 1, s.}; usually stout, more or less curved 

 or angulated in the middle ; evenly rounded off at each end ; ranging in size from 

 about 0'026 millim. by O'OOG millim. (or perhaps even less) to about 0'2G millim. by 

 0'02 millim. (A few long and very slender spicules, oxeote and strougylote, occur in 

 the interior of the sponge; they are probably abnormal forms of the strongyla, with 

 which they are connected by intermediates.) 



(2.) Microxea (Plate IX., fig. 1, m.) ; fusiform and usually angulated in thr middle, 



