41 G 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. 



