474 " THETIS " SCIENTIFIC RESULTS. 



continuous sponge substance. The surface generally is furnished 

 with abundant conuli about 5 mm. high and from 2 to 3 mm. 

 apart. The conuli are more or less connected by narrow ridges ; 

 the depressions between are deeply concave and are often trian- 

 gular in outline, with a tendency here and there to form inter- 

 rupted longitudinal grooves. The dermal surface is slightly 

 rugose, finely porous, with a few scattered oscula which are 

 generally situated in the depressions. 



Skeleton consisting of a series of densely packed cylindrical 

 fibres of stylote spicules. The diameter of the main fibres 

 ranges from 0*2 to 0'3 mm.; the secondaries are about 0*1 mm., 

 whilst the connecting fibres are diffused and consist of bands of 

 ill arranged spicules. The mesh is more or less rectangular and 

 usually about 05 mm. or more in diameter. The primary and 

 secondary fibres terminate at the surface in numerous aculeations. 

 Each fibre is invested with scattered C-shaped spicules, and the 

 latter, together with the anisochelse and styli, are abundant in 

 the choanosome and also in the dermal membrane. 



Megascleres : — fusiform styli with occasionally a few subtylo- 

 styli 0*35 to 0'4 mm. long by 015 mm. in diameter in the centre 

 of the spicule. 



Microscleres : — sigmata either contort or C-shaped, usually the 

 latter are the most noticeable; size 0'15 by 0"08 mm. Aniso- 

 chelfe 0*045 mm. in length; the flukes are about 0*025 by 0"01 

 mm. and the shaft 0*015 mm. long. 



PHELLODERMA, Ridley and Bendy. 



PHELLODERMA POLYPOIDES, sp. nov. 



(Plate xliv., fig. 12). 



Station 36. 



Sponge with a short broad stem attached to fragments of 

 shells ; the distal third or half presents a series of five finger-like 

 processes from 30 to 50 mm. long and 5 or 10 mm. in diameter ; 

 the larger branches are somewhat flattened and taper gradually 

 to subacute points, which are apparently osculiferous. 



Dermal surface somewhat rugose and furnished with numerous 

 minute dome-shaped elevations ; the latter give the sponge an 

 appearance like that of an Alcyonarian coral with retracted 

 polyps. The elevations are darker in colour than the ground, and 

 are about 0*5 mm. in diameter and 1*0 mm. or more apart. 



Texture close, hard, and rather tough. Colour mottled-brown. 



