46 R. KIRKPATRICK. 



and frequently have a small central knob. (Figures are given for convenient comparison 

 with the nearly related new species, G. fimbriatus, described below.) 



The pores, abundant over the areas roofing over the spaces between the main 

 fibres, are circular or oval and vary from 30-70 n in diameter ; the subdermal spaces 

 are about a millimetre in depth ; there are also smaller and shallower subdermal spaces 

 between the more central terminal branches of the main fibres. The flagellated 

 chambers, which are unusually small, viz., about 23 /u in diameter, are spheroidal and 

 eurypylous ; as seen in section they line labyrinthine folds and spaces. 



The cellules spheral euses attain the large size of 35 n in diameter, the spherules 

 also being of considerable size, viz., 8 /*. 



Sections of the branches show nests containing 30-50 embryos, forming conspicuous 

 red patches in the sections in balsam ; each embryo is about 235 M in diameter, and of 

 yellowish colour, though red in masses. Some contain rhaphide-like oxeas. On the 

 surface of the figured specimen are several little hemispherical pits from 2-5 mm. in 

 diameter ; these are probably the exposed surfaces of the embryo-containing cavities, 

 and not due to parasites. 



The specimens were dredged in McMurdo Bay, in depths up to 20 fms. The 

 'Belgica' obtained a specimen from Lat. 70 23', Long. 82 47' W., from 500 metres. 



GELLIUS FIMBRIATUS. 



(Plate XVII., figs. 2, 2a, and Plate XXIV., fig. 2a-b.) 

 1907. Gelliusfmibriatus Kirkpatrick (10a. p. 286). 



Sponge in form of a thick triangular cake, or conico-cylindrical. Texture soft, 

 easily broken. Colour in spirit, pale buff. 



Surface level, or almost imperceptibly hispid ; showing through the dermal 

 membrane a somewhat areolated pattern, each areola being formed by the end of a 

 main fibre giving off fimbriated twigs which roof over the subdermal spaces between 

 the main fibres. A few circular oscules about 5 mm. in diameter and with slightly 

 raised rims occur. 



Skeleton formed of longitudinal lines of flat, loose, band-like main fibres, with 

 an irregular and obscure reticulation of single spicules between. The main fibres 

 spread out in a paniculate manner a little below the dermal membrane. 



Spicules. Megascleres. Oxeas, 537 x 16'25ju., slightly bent or curved at 

 centre, attenuating gradually to sharp points. * 



Sigmata varying in size, the largest being 40 p. long, 1 7 G p, broad, and 1 '76 p. 

 thick, with one or more angular bends in the curve, usually one end of the shaft with 

 an angular bend, the other end curved. 



The specimen selected as the type of this species has a flattened angular pad-like 

 body, 10 cm. long. 4'5 cm. broad, and 2' 5 cm. thick; it apparently lay free on the 

 bottom. 



