SPONGES — WHITELEGGE. 515 



meter, and contain about 6 or 8 spicules in a row ; the secondaries 

 are scarce and ill-defined except near the surface ; they are 

 generally bi- or trispicular and measure 05 mm. The connecting 

 fibres are mostly unispicular and occur at fairly regular intervals, 

 being arranged at right angles ; the mesh is square or oblong, 

 and is usually about 0'3 by 0-4 mm. in diameter. 



Megascleres : — (1) Straight, smooth styli of the fibres and 

 dermis ; size 0-9 to 1-05 by 0-02 to 0-025 mm. 



(2) Slightly curved, smooth styli of the connecting fibres; size 

 0-3 to 0-5 by 0-01 mm. 



(3) Short, straight, echinating styli; the shaft, base, and the 

 abruptly-pointed apex are more or less covered with recurved 

 spines ; size 0'5 to 0"6 by 0*02 mm. 



RASPAILIA DICHOTOMA, sp. nov. 



(Plate xlvi., fig. 36.) 



Station 44. 



Sponge with a small discoidal base, a short peduncle, and 

 numerous curved, subcylindrical, dichotomous branches, chiefly 

 disposed in a plane. The figured specimen is 200 mm. high and 

 about 70 mm. wide; the branches and peduncle vary from 3 to 

 5 mm. in diameter ; the apices are more or less acutely pointed. 

 Surface reticulated, with irregular honeycombed or villose 

 patches here and there, which are frequently interrupted by 

 shallow, longitudinal grooves, the latter presenting a few small 

 pores. Oscula scattered, about 1 mm. or less in diameter. 



Texture hard, incompressible, and somewhat brittle; colour 

 greyish -yellow. 



Skeleton composed of a dense series of slender primary fibres 

 about 0'15 mm. in diameter and 0"2 mm. apart; scattered 

 spicules are present in such numbers that the main fibres cannot 

 be traced in the central regions of the branches ; the secondaries 

 are more definite, especially near the margins ; they are 0'05 

 mm. in diameter and a little more apart at the surface ; they 

 terminate in long, whispy tufts of slender styli ; these are crossed 

 and inlaced by short, curved oxea. 



Megascleres: — (1) Straight, smooth styli, variable in dimen- 

 sions ; size 0-35 to 0-7 by 0-008 mm. 



(2) Smooth styli ; size 0-2 by 0-015 mm. 



^3) Curved oxea ; size 0-2 by 0-007 mm. 



