70 THE DEPTHS OF THE SEA. [chap. iI. 



dredged in lat. 59 c 30', long. 7° 20' (Station 12), with a 



depth of 530 fathoms and a 'warm area' temperature 

 of 6°*1 C. The dredging- here was most interesting. 

 The bottom was for the first time 'Atlantic ooze,' a 

 fine bluish-grey tenacious calcareous mud, with some 

 sand and a considerable admixture of Globiy evince. 

 Imbedded in this mud there came up an extraordinary 

 number of silicious sponges of most remarkable and 

 novel forms. Most of these belonged to an order 

 which had been described by the writer a couple of 

 years before as ' Porifera vitrea,' a tribe at that time 

 but little known, but which have since become very 

 familiar to us as denizens of the abyssal zone. 

 Working from more extended data, Professor Oscar 

 Schmidt afterwards defined the group more exactly 

 as a family, under the name of Hexact'uieUidce — the 

 term which I shall here adopt. 



The relations and peculiarities of this singular 

 group will be fully discussed in a future chapter. 

 The most characteristic forms which we met with on 

 this occasion were the beautiful sea-nests of the 

 Setubal shark-fishers, Holtenia carpenteri, Wy. T. 

 (Fig. G), and the even more strange Hyalonema 

 lusitanicum, Bakhoza de Bocage, closely related to 

 the glass-rope sponges of Japan which have so long 

 perplexed naturalists to determine their position in 

 the animal series, and their relation to their constant 

 companion the parasitic l J alythoa. 



Holtenia carpenteri is an oval or sphere 90 to 100 

 mm. in height, with one large oscular opening at the 

 top about 30 mm. in diameter, whence a simple 

 cylindrical cavity cupped at the bottom passes down 

 vertically into the substance of the sponge to the 



