from the Antarctic Sea. 413 



& 2). Dermal sarcode cribriform, from the number of minute 

 "pores" in it (fig. 4), with here and there a large circular vent 

 (fig. 2, c c c) , Summit presenting three or more large vents, 

 which branch off internally into the excretory canal-system 

 (3, a a a). Base furnished with tufts of long spicules, anchor- 

 and fork-headed respectively, some of which have their heads 

 in the sponge and their shafts free, and vice versa (fig. 2, e). 

 Internally cavernous, arising from a much dilated state of the 

 excretory canal- system, whose extremities are peripheral, 

 where the sponge-structure appears to be densest. Spicules of 

 three kinds, viz. : — 1, acerate, very slightly curved, and long- 

 pointed (fig. 5) ; 2, anchor-headed, of two forms, viz. one with 

 thick arms, hastiform (fig. 7), the other with the arms more 

 expanded (fig. 8) ; 3, tri-fbrk-headed, one prong much longer 

 than either of the other two, which are equal (fig. 6) . No bi- 

 hamates. The first or acerate spicule is chiefly confined to the 

 body, and the two other kinds to the surface, being longest 

 and most numerous at the base. Thus the spicules generally 

 vary much in length. The largest acerate form averages 

 l-20th of an inch in the adult sponge (fig. 9) ; and the longest 

 fragment of shaft found with anchor-head attached did not 

 exceed 1^ inch (fig. 10). Generally the longest of these spi- 

 cules do not appear to have been more than li inch in length. 

 The hastate form of anchor-head appears to be chiefly confined 

 to the body, and the expanded or grapnel form to the free ex- 

 tremities of the spicules of the tufts at the base of the sponge. 

 Size of young Tethya antarciica figured l-16th of an inch in 

 diameter exclusive of the tufts at the base — inclusive of the 

 tufts, 5-48ths, or about 1-lOth of an inch long (fig. 1). Size 

 of \2iXg<is>\, fragment of adult sponge 4 inches long. 



Hah. Marine ; deep sea, in 206 to 300 fathoms. 



Lioc. Antarctic Ocean, in lat. 74|° and 77|° S., and long. 

 175°W. 



Ohs. I have little to add to what has already been stated of 

 this sponge. The description of the form is taken from that 

 of the young one found in the parent, and the details of struc- 

 ture from the adult fragments ; so that the whole is almost 

 as complete as if we had had the adult entire. Generally the 

 sponge corresponds to the Tethyadoi of Avhich T. cranium is 

 the type, modified more or less by a great dilatation of the 

 excretory canal-system, in which it more particularly agrees 

 with Carteria and Holtenia. It is also tufted at the base 

 for fixture in the mud and sand ; but in this it does not 

 resemble these sponges any more than Tethya dactyloidea^ 

 which not only is similarly tufted at the base, but presents a 

 large vent at the summit, through which the excretory system of 



