Catalogue of Non^Calcareous Sponges. 257 



by - 003 mm. including the spines ; (b) longer and slenderer 

 spined microxea, slightly curved or even angulate, measuring 

 about 0-06 by 0-003 mm. These spicules remind one forcibly of 

 those of Higginsia. The microscleres are abundantly scattered 

 both in the deeper tissues and in the dermal membrane, but they 

 are so small that they form no conspicuous part of the skeleton. 

 The short rod-like forms are the most plentiful. 



R.N. 479 (x, 20 f.; "orange-chrome"); 1187; also dried 

 specimen. 



Genus Pronax, Gray.* 



Sponge of boring habit ; megascleres tylostylote, microscleres 

 asters (spirasters). 



Pronax carteri, n. sp. 



Vioa johnstonii, Carter, A.M.N.H., December, 1886, p. 458. 



The sponge described by Carter is certainly quite distinct from 

 Schmidt's Vioa johnstonii, having tylostylote in place of oxeote 

 megascleres, in virtue of which it falls under Gray's genus 

 Pronax. As I have seen no specimen I must content myself 

 with referring to Carter's original description. 



ADDENDA. 



The following have, owing to the difficulty of determining 

 their true position, been accidentally omitted from their proper 

 places in the first two instalments of this catalogue. 



Genus Rhaphisia. 



(Continued from Part I., p. 257). 



Rhaphisia pallida, n. sp. 



Sponge massive, sessile, irregular. Surface uneven ; rugose, 

 warty or conulose, but subglabrous. Vents inconspicuous, 

 scattered on prominent parts. Texture compact but compressible 

 and resilient, soft. Colour in spirit pale greyish-yellow or white. 

 In life, usually at any rate, pale grey. 



Skeleton very lax and rather scanty ; consisting of slender 

 megascleres loosely scattered, or in loose whisps which run 



* Proc. Zool. Soe. Lond. , 1867, p. 526. 



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