294 ZOOPHYTES, SPONGES, ETC. 



dredged in quantity on another occasion, in the same 

 sea, at 1070 fathoms. 



Though they live under an enormous pressure, the 

 soft parts and skeleton (corallum) of these deep-sea 

 corals are far from being always delicate and fragile. 

 For instance, in Stephanotrochus (Fig. 92), which is 

 a characteristic deep-sea genus, the soft parts are 

 thicker and more fleshy, and the skeleton is harder 

 and denser than in most reef corals. But on this 

 point, as usual, no hard and fast generalisations can 

 be made, for in Bathyactis (Fig. 93), which is also 

 a characteristic deep-sea genus, the soft parts are 

 excessively delicate, and the skeleton is exquisitely thin 

 and lace-like. 



Among the noteworthy corals of the Andaman 

 depths is Deltocyathus andamanicus (Fig. 94), dredged 

 in 172-303 fathoms ; it has a most beautifully sculptured 

 disk-like corallum, and, perhaps, is not really distinct 

 from Deltocyathtis italicus, a fossil species from the 

 Tertiary rocks of Italy, which still lives in the depths 

 of the Atlantic. 



The majority of deep-sea Sponges belong to the 

 class Hexactinellida, elegant forms whose skeleton con- 

 sists of a delicate trellis-work of translucent six-rayed 

 spicules of flint, of which the beautiful Venus' flower- 

 basket and the curious glass-rope sponge are the most 

 familiar museum examples. These sponges are rooted 



