SPONGES — WHITELEGGE. 467 



Texture firm and fairly resilient. Colour dull dark cream. 



The skeleton consists of a rather open network of dense 

 spicular fibres with very little visible spongin. The mesh varies 

 in shape from subcircular to oblong, and usually measures, 

 between the primary fibres, from 0*8 to 1 mm. in diameter. The 

 main fibres are densely packed with stylote spicules and are 

 from 0'2 to 0*4 mm. in thickness ; the secondary and connecting 

 fibres consist of whispy bundles from 0'5 to 1 mm. in diameter; 

 there are also many spicules in the ground substance and also 

 ^chinating the fibres, but in a most irregular manner. 



Megascleres ; — styli very variable in thickness, but usually 

 about 0'4 mm. in length ; they are subfusiform and gradually 

 sharp-pointed. 



Microscleres : — consist of three sizes of anisochelse, two of 

 which are arranged in rosettes. The larger clusters are about 

 0'25 mm, or more in diameter and the smaller O'l. The individual 

 spicules of the former have three grapnel-like teeth, a curved 

 shaft with a peculiar grooved head. The shape and general 

 contour is exactly like a spicule figured by Bowerbank from West 

 Australia.* The smaller rosette spicules are similar in shape to 

 larger kind, but the teeth are either absent or rudimentary. 



The third kind of anisochelae is somewhat like a C about 0'02 

 mm. long with a short hook at the apex and a slightly longer one 

 .at the base ; the latter is almost straight, with its apex pointing 

 towards the upper part of the c. These peculiar spicules are 

 scattered throughout the body of the sponge. 



ESPERELLA CYLINDRICA, sj). nov. 



(Plate xliii., fig. 8.) 



Station 44. 



Sponge consisting of a cylindrical stem 300 mm. in length and 

 from 10 to 20 mm. in diameter. The specimen is a washed-out 

 example denuded of its epidermis and retaining but little of its 

 sarcode. The external surface is minutely conulose, rather 

 openly reticulate, and pi'esents a series of depressions about 5 mm. 

 deep and 15mm. apart; these appear to be the oscular areas. 

 Texture resilient, rather tough. Colour light-sponge. The 

 skeleton has a radiate appearance when viewed by transmitted 

 light, the central fibres of the axis can be traced for a considerable 

 distance and finally they terminate in tufts at the surface. 



• Bowerbank — Mon. British Spongid^e, i., 1864, p. 249, pi. vi., fig. 135. 

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