TETRAXONIDA. 33 



tbey pass upwards; the separate fibres of the main bundles about 80 m tliicli. The 

 main bundles joined at right-angles by secondary fil:)res, 1-3 spicules thick. Spongin 

 not perceptible. Ectosomal skeleton formed of circles of strongyles, the spicules isolated 

 or in fan-like wisps, arranged partly vertically, partly tangeutially round the pore areas ; 

 the vertical spicules usually isolated, and the tangential ones in wisps. On drying the 

 sponge, the edges of the pore areas stand up sharply, the areas themselves sinking in, 

 giving a pock-marked aspect to the surface. 



Spicules. Megascleres. Choanosomal styles, 402 x 1 3 /u, curved at about one- 

 fourth of the length from the round end, smooth, but occasionally with a few spines 

 about the head. 



Ectosomal strongyles, 2G1 x G • 5 /«, smooth, occasionally slightly swollen at each 

 end. 



Microscleres. None. 



The single sj^ecimen is in the form of a squarish mass of thick Heshy flabello- 

 palmate or digitate lobes ; the height is 18 cm., and the breadth 13 cm. The Habellate 

 fronds are obviously formed of fused tubular digitations, as can be seen from the 

 oscules along the upper edge and from the faintly indicated longitudinal grooves down 

 the sides. The walls of the oscular canals are smooth and lined with numerous 

 orifices of exhalant canals, about -3 mm. in diameter. The arrangement of the pores 

 in circular areas each surrounded by a zone of ectosomal spicules is not common in 

 Tedania ; it occurs in the second new species descriljed below, and something of the 

 kind is found in Tedania tenuicapitata Ridley (15a. p. 124), from the Straits of 

 Magellan. In the present species this feature is so well marked as to give the surface 

 a pock-marked appearance. 



The rhaphides, usually so characteristic of Tedania, have entirely disappeared ; 

 but the loss of microscleres is of such frequent occurrence that it has not seemed 

 necessary to create a new genus or subgenus to include such forms ; though, perhaps, 

 the more or less definite arrangement of the ectosomal spicules might, in the present 

 instance, necessitate such a course. 



The specimen was dredged near Winter Quarters, 10 fms. 



Tedania coulmani. 



(Plate XXL, fig. 2. Plate XXV., fig. 2a-V.) 



r.)(i7. Tedania coulmani Kirkpatrick (10a. p. 2S0). 



Description. The single specimen is in the form of a finger-like fragment 

 5 "5 cm. long and 17 cm. in its greatest thickness. The colour is dirfy gray, and the 

 consistence soft. The surface shows the same circular pore-sieve areas as in T. variolosa. 

 Along one side of the sjjonge the surfiice has been torn away, exposing an exhalant 

 canal running along the length of the specimen, but the terminal oscule has apparently 

 been torn away. 



2 E 2 



