188 THE DEPTHS OF THE SEA. [cHAP. IV. 
more than we yet do of the extension both in time 
and space of the fauna of deep water before we can 
come to any certain conclusion on these questions. 
Dredging across the entrance of the Strait of Gib- 
raltar in 477, 651, and 554 fathoms, Stations 31, 32, 
and 33, with a bottom temperature of 10°38, 10° 1, 
and 10°0 respectively, many remarkable forms were 
dredged, including a very elegant sponge, apparently 
allied to, if not identical with, Oscar Schmidt’s 
Caminus vuleani, and some beautiful forms of the 
Corallio-spongize, which will be noticed in a future 
chapter. Station No. 31 yielded a sponge form 
which recalled the branching heather-like Cladorhiza 
of the cold area off Féroe. Chondrocladia virgata 
(Fig. 36) is a graceful branching organism from 
twenty to forty centimetres in height. A branching 
root of a cartilaginous consistence, formed of densely 
packed sheaves of needle-shaped spicules bound 
together by a structureless organic cement, attaches 
the sponge to some foreign body, and supports it 
in an upright position; and the same structure is 
continued as a solid axis into the main stem and the 
branches. The axis is made up of a set of very definite 
strands like the strands of a rope, arranged spirally, 
so as to present at first sight a strong resemblance to 
the whisp of Hyalonema ; but the strands are opaque, 
and break up under the point of a knife; and under 
the microscope they are found to consist of minute 
needle-like spicules closely felted together. The soft 
sponge substance spreads over the surface of the axis 
and rises into long curving conical processes, towards 
the end of which there is a dark greenish oval mass 
of granular sponge matter, and the outline of the 
