Ik 





THE SPOMGES. 



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root tuft is 330 mm. long, 6 mm. thick, near the body, and includes about 

 50 spicules, most of which are thick, having a greatest diameter of about 

 1 mm., although much slenderer ones are intermingled. At its base the 

 tuft is embraced by a single Actinia-like anemone of a yellow-brown color 



and firm leathery consistency. 



A marginal ridge is sharply defined round the greater part of the gastral 

 surface. The membrane covering the gastral surface is in general a typical 

 reticulum, but in places near the periphery of the surface the reticulum 

 is not developed, the membrane here appearing to the eye dense and per- 

 forated only by scattered oscula about 1.5 mm. in diameter. The mem- 

 brane covers in a relatively large number of efferent canals, the transverse 

 diameter of which at the surface is 5-10 mm. These canals extend more 

 or less vertically into the body, and largely excavate it. Some of them 

 are easily traceable from the gastral surface to the base of the body. 



surface of the body, is a 



reticulum with a somewhat finer mesh than the gastral membrane. • Over 

 a considerable part of the surface the dermal membrane has been abraded, 

 disclosing the canals beneath. These, presumably afferent, canals are in 

 general smaller than the canals opening on the gastral surface. At the 

 base of the body there is a rather inconspicuous collar-pad, surrounding 

 the root tuft and containing the characteristic acanthophorae. 



The entire specimen from Station 3363 is a saucer-shaped mass, with a 

 flat upper and convex lower surface. The root tuft has been torn out, 

 leaving an evenly bounded aperture, 6 mm. wide, about in the centre of 

 the lower surface. The sponge body has a depth of 40 mm., the hori- 

 zontal diameters being respectively 85 mm. and 65 mm. In other respects, 

 the description given of the specimen from Station 3376 applies to this 

 specimen. 



The 



dermal membrane, covering the lateral 





The letter specimen from Station 17 (1900 cruise) resembles in essential 

 shape the one from Station 3363, but is even flatter. ' The depth is 15 mm., 

 the horizontal diameters respectively 80 and 60 mm. The root tuft has 

 again been torn out, leaving a somewhat irregular aperture 7 mm. in 

 diameter. The gastral membrane, covering the upper surface, appears 

 continuous and not reticular, the probable explanation being that the 

 apertures are closed. The dermal membrane, covering the under surface, 

 is reticular as in the other specimens. Toward the periphery the body 

 thins away to a sharp margin, which is somewhat injured. The other 





