TETRAXONIDA. 47 



The upper surface alone shows the areolated appearance below the dermal mem- 

 brane, the under surface being nearly opaque. 



A second specimen is conico-cylindrical *in shape, 11 cm. long and 3 cm. in 

 diameter, the lower end being broken off. This specimen also apparently lay on the 

 bottom along part of its length, as the pore surface extends all round only at the 

 upper end of the specimen. 



A third .specimen from Coulman Island is fan-shaped, 7 cm. high, 3*5 cm. thick, 

 7 cm. broad at the upper edge, and 3 cm. broad at the l)ase, where it is attached to two 

 small stones. The surface is quite worn away, and the body of the sponge full of deln-is. 



An "areola" with its central node (the end of the main fibre) and lateral 

 branchlets occupies on an average an area of G x 4 mm. 



The ends of the main fibres are arranged in linear series. 



The dermal membrane is separated about 3 mm. from the fioors of. the large 

 sub-dermal spaces, and the band-like supporting pillars are aljout 2 mm. broad. A 

 vertical section gives the appearance of a miniature "hall of a thousand columns." 

 The dermal membrane on the under surface of the sponge contains scattered oxeas 

 arranged tangentially. 



The pores vary a good deal in size and .shape, being oval or round, and 45-120 ju, 

 in diameter. The flagellated chambers are spheroidal, eurypylous, and about 25 [x in 

 diameter. The triangular cushion-like shape of the type recalls to mind Gellius 

 Jiagellifer (R. and D.), but there are no flagellate sigmata in the new species. 

 G. rudis (Topsent) has a much firmer and denser structure ; the oxeas are shorter, 

 thicker, and with tornote ends, and the sigmata are more slender and with uniform curve. 



Dredged near Winter Quarters, off Hut Point in 12-20 fms. ; also off Coulman 

 Island in 100 fms. 



Gellius pilosus. 



(Plate XVII. , fig.s. 3, 3a, and Plate XXIV., fig. 3a-c.) 



1907. Gellius pilosus Kirkpatrick (10a. p. 287). 



Sponge in form of an erect flattened triangular or elongate lamella divided or 

 digitate at the upper edge. 



Consistence soft, fleshy, compressible. 



Colour in spirit, dirty white or very pale yellow. 



Surface finely conulose and pilose owing to the projection of the ends of the main 

 skeleton fibres about 1 mm., the conules being about '6 mm. apart from each other. 



A few oscules about 1 mm. in diameter, on a level with the surface. 



Skeleton formed of slender main axial fibres on an average about 2-5 spicules 

 thick, curving out to the surface where they form the pile, and of secondary fibres, 

 usually one, but sometimes two or three spicules thick, at right angles to the main 

 ones, with which they form oblong scalariform meshes. Spongin well developed at the 

 nodes of the network. 



VOL. IV, ■^ 6 



