108 OKHAMANDAL MARINE ZOOLOGY REPORT PART II 



while in the Indian Ocean form the oxea measure less than 0-2 mm. and the sigmata 

 usually less than 0-025 mm. 



It appears to me that these differences are too slight to be of any specific value in 

 themselves, especially as I have in my possession (in Mr. Carter's cabinet) a preparation 

 from a specimen from the Devonshire coast (Budleigh Salterton), in which the oxea 

 measure only 0-14 by 0-006 mm., while the sigmata measure about 0-03 mm. from 

 bend to bend. 



On the other hand, I think that it may be possible to distinguish an Indian Ocean 

 species characterised by its robust growth and large oscular tubes. For this form I 

 adopt Hentschel's name ridleyi, though I must regard it as very doubtful whether all 

 the specimens from the Indian Ocean which have been referred by various authors to 

 Gellius fibulatm can now be referred to Gellius ridleyi. Mr. Hornell's collection contains, 

 as we have already seen, another Gellius which seems to be quite distinct from G. ridleyi, 

 and which I regard as a mere variety of G. fibulatus, and I consider it highly probable 

 that the specimens which I described from Ceylon in 1905 belong to G. fibulatus rather 

 than to G. ridleyi. 



Previously known Distribution. Indian Ocean (?) (auctorum) ; Aru Islands 

 (Hentschel). 



Register Number, Localities, &c. XVII. 1, Kiu, littoral, 24.12.05 ; XXVI. 5, 

 Adatra Reef, 25 Dec. '05 ; XXXIII. 7, Dhed Mora and adjacent rocky ground between 

 Beyt and Aramra, 1 fm., 21.12.05. 



15. Gelliodes fibrosa Dendy. 



Gelliodes petrosioides, var fibrosa Dendy [1905]. 



In my report on Professor Herdman's Ceylon sponges I suggested that my Gelliodes 

 petrosioides var. fibrosa might, when better material was forthcoming, have to be con- 

 sidered as a distinct species. The occurrence of two fairly good specimens in Mr. 

 Hornell's collection leads me to carry out this suggestion. The two specimens come 

 from the same locality and are possibly parts of the same. One (R.N. XXXIV. 6) 

 is an irregular, flattened sponge which has been attached to the substratum at a few 

 points only, and with a tendency to throw off digitiform processes. The upper surface 

 is almost flat and minutely conulose. It bears several fair-sized but shallow vents, 

 whose margins are very slightly raised above the general surface. The specimen 

 measures about 48 mm. in length by 28 mm. in greatest breadth and 10 mm. in average 

 thickness. Texture rather soft and compressible. Colour in spirit (after formalin) 

 very pale brown. The second specimen is an irregularly subcylindrical fragment (?), 

 about 56 mm. in length by 7 mm. in diameter in the middle, broadening out suddenly 

 to about 18 mm. at one end. 



The skeleton arrangement is identical with that of a typical Pachychalina. The 

 main skeleton consists of a subrectangularly meshed network of stout spicular fibre 



