of tlie National Antarctic Expedition. 289 



larger, the type specimen, consists of a basal bulbous portion, 

 13 mm. long, 7 mm. broad, and S mm. high, from one side 

 of which arises a rather thick-walled fistula 13 mm. high and 

 5*5 mm. in diameter ; at the opposite side is a broken circular 

 area, from which, in all probability, a second fistula arose ; 

 lastly, between these two is a small raised knob with a rounded 

 orifice on one side of it. The narrow oscular canal is not 

 central, but along one side of the thick-walled complete fistula. 



Tlie second specimen is tubular, with a slightly enlarged 

 solid base, whence arises a fistula ; the total length is 2 cm., 

 and diameter "5 cm. No pores are discernible ; the subdermal 

 spaces are about '2 mm. in depth. 



The eurypylous flagellated chambers are 23 jx in diameter. 

 Cellules spheruleuses, 8-9 ^ in diameter, are common. 



There is no bast- like subdermal layer as in Oceanapia 

 mollis^ Dendy, and the spicules of the latter are smaller, the 

 oxeas being 200 X 8yLt, and the sigmata only 16 /u.. Lundbeck 

 describes two species of Gellius with fistulse, and with a well- 

 developed dermal bark, viz, G. luridus and G. microtoxa, 

 but both these species have toxa in addition to sigmata. 



Locality. Winter Quarters, 25-30 fath. 



Oceanapia tantula, sp. n. 



The sponge consists of five small fragments of tubes, the 

 longest of which is 8 mm. in length, by 4 mm. in diameter: 

 thiee of the pieces are hollow, thin-walled, and tubular; the 

 other two are solid. One of the solid pieces seems to belong 

 to the top of a fistula. 



The colour is transparent white. 



Skeleton. — The dermal layer is composed of a chitinous- 

 looking membrane with strongyles lying tangentially, usually 

 in one layer and densely packed, but sometimes more or less 

 scattered. 



The white strands of the loose subdermal reticulum are 

 visible through the surface. They are longitudinal, and only 

 anastomose occasionally. The strands are less than '1 mm. 

 in diameter. They vary in composition j in some parts being 

 composed of strongyles smaller than those of the dermal 

 layer, in other parts of smooth trichodragmata, or again of 

 strongyles, amphityles, and trichodragmata. The pale trans- 

 parent choanosomal tissues are crowded with small spined 

 rliaphides. 



Spicules. — Megascleres : strongyles, 437 x 19//., slightly 

 fusiform, curved once or sometimes twice. Occasionally one 

 end is pointed, the spicule becoming a style. 



Amphityles, 395 x 7*25 /it, slightly fusitbrm ; heads 13 fM 

 long, 9' 75 /u, broad. 



