Sponge-fauna of Madras. 159 



common on the large pearl-bank in from 6^ to 9 fathoms ; 

 and I have met with it once or twice on rough ground on 

 other parts of the coast ; it is usually attached to some bit of 

 rock, and is always, when alive, of a uniform bright orange- 

 colour. It turns black an hour or two after being taken out 

 of the water. The largest specimen I have seen was about 

 as large again as the one you have. The general shape and 

 colour are always the same " *, 



The species is undoubtedly referable to the genus Axinella^ 

 of which, in both form and arrangement of the spicules, it is 

 a typical member. It is represented in the present collection 

 by four specimens of a dark brownish colour, ranging in dia- 

 meter from 55 to 130 millim., and in height from 42 to 130 

 millim. All are distinctly pedunculate and have the same 

 general external appearance although varying widely in de- 

 tails of form. One specimen is almost a facsimile of that 

 figured by Bowerbank and is, moreover, labelled '^ colour 

 orange," which is a very satisfactory confirmation of Mr. 

 Holds worth's statement. A second specimen is also cup- 

 shaped, but the wall of the cup, instead of simply undulating, 

 is proliferated outwards into large, branching and anastomos- 

 ing, vertical lamellse. 



The most remarkable variation in external form is, how- 

 ever, exhibited by a specimen which is not cup-shaped at all, 

 but consists of a number of vertical lamellee inclined at various 

 angles to one another and attached to a stout peduncle. The 

 surfaces of these lamellee are furrowed towards the upper 

 margin by numerous deep longitudinal grooves about 1*5 millim. 

 broad, in which lie numerous minute oscula. In a few places 

 only the grooves are very short and stellately arranged, these 

 stellate grooves occurring lower down on the specimen than 

 the longitudinal ones. I have thought it desirable to give an 

 illustration of this remarkable form (PL XI. fig. 1). 



As the species has already been pretty fully described, I need 

 give no further details except with regard to the spicules. 

 These are fairly stout, gradually sharp-pointed, usually curved 

 styli, averaging about 0*315 by 0*0157 millim. in size. The 

 small and slender styli ("acuates"), mentioned by Bower- 

 bank, are scarce in my specimens ; no doubt they are young 

 forms of the larger spicules. 



FJiahelUa Ridleyi, n. sp. (PI. XI. figs. 2, 2 a.) 



Sponge (PI. XI. fig. 2) erect, flabellate, forming thin fronds. 

 There are in the collection two specimens, measuring 80 millim. 



* Proc. Zool. Soc. 1873, p. 29. 



