DEN DY NON-CALCAREOUS SPONGES 113 



reticulate. The texture is firm and rather coarse, the colour in spirit (after formalin) 

 light brown. 



The skeleton is a confused reticulation of large oxea which show a strong tendency 

 to arrange themselves in coarse fibres. There is a very well developed dermal reticu- 

 lation of spicular fibre varying in diameter. 



The oxea are slightly curved, gradually and sharply pointed at each end, and 

 commonly measure about 0-77 by 0-023 mm., although variable. 



R.N. XXXII. 5 is more massive, with a more compact and less distinctly fibrous 

 skeleton, and comes very near to Ceylon specimens of Halichondria panicea var. 

 megalorhaphis collected by Professor Herdman [Dendy 1905]. Most of the specimens 

 are in a very poor state of preservation, owing, doubtless, to the use of formalin as a 

 preservative. 



Previously known Distribution of the Species. Almost cosmopolitan. 



Register Numbers, Localities, &c. XVII. 3, Kiu littoral ; XX. 3 a, b, Adatra ; 

 XXIX. 4, 3f-4 fms. N. of Poshetra, 20.12.05 ; XXXII. 5, off Beyt ; XXXIV. 8, 

 Channel, W. side of S. end of Beyt Island, 3-4 fms., 3.1.06. 



22. Halichondria reticulata Baer [1905]. (Plate II., Figs. Ua, 14&.) 



The sponge, of which there is a good deal in the collection, consists of slender, 

 irregular, often tortuous, creeping branches, which frequently anastomose and unite 

 with one another in irregular, massive lumps (Figs. 14 a, 14 b). Individual branches 

 are usually about 2 or 3 mm. in diameter. They are generally subcylindrical, but 

 may be flattened ; they may be bluntly rounded at the extremity or drawn out into a 

 long point. The surface is finely granular and marked by ramified, meandering, sub- 

 dermal canals. Vents minute, few, scattered. The colour in spirit is very pale yellow ; 

 the texture rather compact and fleshy, but soft and compressible. 



The main skeleton consists of slender oxea, partly scattered quite irregularly 

 and partly in loose wisps or fibres which run towards the surface. The dermal 

 skeleton consists of irregularly scattered spicules of the same kind, lying tan- 

 gentially and crossing one another in all directions. 



Spicules. Slender oxea ; very slightly curved, gradually sharp-pointed at each 

 end, measuring about 0-21 by 0-006 mm. ; very uniform in shape and size. 



This species seems to be well characterised by its peculiar mode of growth 

 and by the small size of its spicules. Although Baer's description is very brief, 

 and although the spicules in the Okhamandal sponge seem to be somewhat 

 stouter, I think the identification is a fairly safe one. Baer observes that the 

 flagellate chambers are round and 0-03 mm. in diameter, and that the ground 

 substance is homogeneous and filled with round granule-cells. 



The histological features of the Okhamandal sponge, which I have studied by 

 means of paraffin sections of material stained with borax-carmine, confirm the identi- 



