I20 



■ENDEAVOUR" SCIENTIFIC RESULTS. 



n 



n 



In the present condition of the sponges, the oscula are 

 closed, and not readily percei\ed ; but their presence is, in 

 every case, indicated by longitudinal furrows and puckers of 

 the extremity of the processes bearing them, and is, of course, 

 readily demonstrated by sectioning. Of the specimens of the 

 present series, the largest and the smallest are those which 



depart most from the mean form. 

 The former is sub-elliptical in 

 horizontal outline, and in 120 mm. 

 in height ; the principal diameters 

 of its base are 140 mm. and 90 

 mm. respectively, whilst the cor- 

 responding measurements of its 

 greatest transverse section are 

 200 mm. and 120 mm. It is fur- 

 nished with more than 100 pro- 

 cesses, the greater number of 

 which are ridge-shaped. The 

 smallest specimen is subfusiforni 

 in shape, and is provided with 

 only four digitiform processes. 

 The consistency in the dry state 

 is, one might say, intermediate 

 between that of cork and pith ; the 

 superficial layer is slightly harder 

 and more friable, but there is no 

 indication of a rind. Ihe colour 

 is pale grey within, and yellowish- 

 grey on the surface. The skeleton 

 is difTuse, without any indication 

 of definite fibres, and consists of a 

 fairly dense and irregular aggre- 

 gation of straight spicules show- 

 ing all gradations between st}li 

 and tylostyli. Even in proximity 

 to the surface there is no well- 

 defined arrangement of the mega- 

 scleres, although a considerable 

 proportion of them stand more or 

 less perpendicularly, with their 

 points (or not infrequently, in the 

 case of the larger spicules, with 

 their basal extremities) impinging on, or barely projecting 

 bcN'ond, the surface. 1 he spirasters are comparati\e]y few in 

 number and arc c-ontined almost exclusi\ely to the external 

 surface and to the walls of the canals immediately beneath 

 their lininsj membrane. 



Fig. 21 — S.inontifonnis. a 

 Larger tylostj'li (basal ex- 

 tremity), b Slender tylo- 

 styli (ditto), c Spined spi- 

 rasters. d Tuberculated 

 spiraster. 



