156 Mr. A. Dencly on the 



ance, but all of them show a more or less strongly marked 

 tendency to form digitate processes. All three resemble the 

 preceding specimens in colour and texture, but in two of 

 them the orange colour is more distinctly pronounced. 



The specimen (PI. IX. fig. 2) which I consider most typi- 

 cal of the variety consists of a number of upright, branching 

 and anastomosing, cylindrical processes, springing from a very 

 irregular, thin, basal lamina, which has overgrown a mass of 

 calcareous debris. The finger-like processes are, at any rate 

 usually, tubular, and sometimes there is an osculum at the 

 summit. All the processes and their branches grow vertically 

 upwards. The height of the entire specimen is about 155 mil- 

 lim., and the greatest breadth about the same, while the dia- 

 meterof the finger- like processes averages about 17 millira., The 

 surface of the sponge is fairly even, and, in addition to being 

 very minutely hispid, is also minutely punctate, the puncta- 

 tion being most distinct on the lower, paler-coloured parts of 

 the specimen. This punctate character is not confined to this 

 specimen, nor even to this variety, but it appears to be a 

 variable feature. 



Of the two remaining specimens of the variety one has the 

 digitate processes very broad and irregular, with a very uneven, 

 corrugated surface ; while in the other the digitate processes 

 are almost obsolete. 



The skeleton is much the same as in the preceding varie- 

 ties, except that the fibres are generally more distinct, and, at 

 any rate in the type of the variety, it is possible to distinguish 

 between primary fibres running vertically to the surface and 

 secondary ones crossing them more or less at right angles. 



The spicules are of just about the same shape and size as 

 in the two preceding varieties. 



Perhaps the most nearly allied of previously described 

 species is Nardo's Suherites massa^'. This occurs in the 

 canals of Venice, and is stated to reach the size of a human 

 head ; it is also of a bright orange colour. Thus it must 

 closely resemble the massive varieties of the present species 

 in external appearance ; but it difiers in the size and form of 

 the spicules, which, in Suherites massa, as evidenced by one 

 of Schmidt's preparations in the British Museum, are much 

 longer and relatively very much slenderer than in S. incon- 

 stans. Another species which resembles 8. mconstans in the 

 great size to which it grows is Bowerbank's Hymeniacidon 

 (^=Spirastrella?) pulvinatus'f, from near Belize. Bower- 



* C/. Schmidt, Spong. adriat. Meeres, p, 67. 



t Proc. Zool. Soc. 1872, p. 126. 



