416 THE DEPTHS OF THE SEA. [CHAP. IX, 
by calcareous cement, so that the sand-grains show 
out, dark and conspicuous, scattered on the surface 
of the white shell. Miliolines are abundant, and 
the specimens of Cornuspira and Biloculina are 
greatly larger than anything which has been hitherto 
met with in temperate regions, recalling the tropical 
forms which abound among the Pacific Islands. 
In the cold area, and in the paths of cold currents, 
foraminifera with sandy tests are more numerous; 
some of those of the genera <Astrorhiza, Lituola, 
and Botellina are gigantic—large examples 30 mm. 
long by 8 mm. in diameter. 
The few hauls of the dredge which we have already 
had in deep water have been enough to teach us that 
our knowledge of sponges is in its infancy,—that those 
which we have collected from shallow water along 
our shores, and even those few which have been 
brought up from deep water on fishing lines, and 
have surprised us by the beauty of their forms and 
the delicacy of their lustre, are the mere margin and 
remnant of a wonderfully diversified sponge-fauna 
which appears to extend in endless variety over the 
whole of the bottom of the sea. I cannot attempt 
here more than a mere outline of the general cha- 
racter of the additions which have been made to our 
knowledge of this group. The sponges of the ‘ Por- 
cupine’ Expedition are now in the hands of Mr. 
Henry Carter, F.R.S., for description; and an ex- 
cellent sketch of the sponge-fauna of the deep Atlan- 
tic, bringing information on certain groups up to a 
late date, has been published by the best authority 
we have on sponges, Professor Oscar Schmidt of 
Gratz. 
