Catalogue of No)i-Calcarcoiis Sponges. 255 



that their ends form a polyo-onal-nieshed reticulation beneath the 

 dermal membrane. The meshes of this reticulation are about 

 1-3 mm. in diameter and the plate-like sandy columns about 0-2 

 mm. in thickness. Little if any spongin cement is developed. 

 Between the sandy plates in the body of the sponge the foreign 

 bodies are few and small, but in the minutely reticulate, porous 

 dermal membrane numerous small foreign bodies occur scattered 

 irregularly. 



Megasckres, few, slender stroiigyla, perhaps sometimes tylota; 

 sparsely scattered through the ground substance and sometimes 

 more abundant in loose tufts at the surface ; measuring about 

 0-U by 0-002 mm. 



I can find no proper microscleres in any of the three specimens. 



R.N. 487 (s. 10, 8 f; "drab-grey"); 499 (s. 6, 6 f ; "clove- 

 brown with a faint wash of green "); 1071 (x A). 



Chondropsis areiu'/era, Carter. 



Choiidropsis arenifera, Carter, A.M.N.H., February, 1S86, 

 p. 122. 



The single entire specimen which I have examined is massive, 

 rounded, and irregular ; with smooth, very minutely reticulate 

 and faintly conulose surface, and large, scattered vents. The 

 texture (in spirit) is rather soft and resilient, sandy, and the 

 colour grey throughout. 



The main skeleton consists of very loose and irregular sandv 

 fil^res (with little or no spongin), running vertically to the 

 surface. The beautifully reticulate, highly porous dermal mem- 

 brane contains numei'ous small, scattered foreign bodies, but 

 there is no distinct dermal skeleton. 



The proper spicules are slender sti-ongyla or tylota, scattered 

 through the ground substance, and more numerous in loose tufts 

 at the surface. They measure about 0-16 by 0'002 mm. 

 Numerous other spicules occur as foreign bodies. There appear 

 to be no proper microscleres. 



Although Carter mentions proper styli as occurring in this 

 species, I cannot find them in the fragment of his specimen sent 

 to me from the British Museum. My own specimen (R.N. 4.34), 

 agrees exactly with the type in microscopical features, even down 

 to the presence of the Algiie mentioned by Carter. 



