THE ROMANCE OF NATURAL HISTORY. 



vast layers of sea- water so thronged with the 

 bodies of a species of Snlpn (S. mucronata) as to 

 present the consistence of a jelly. What their 

 vertical limits were, it was impossible to discover, 

 owing to the speed at which the ship was mov- 

 ing. They appeared to extend deep, however, and 

 in all probability, were of a similar character to 

 the aggregations of what is called whale-food in 

 the higher latitudes. Each of these etalpse meas- 

 ured about half an inch in length ; but so close 

 was their aggregation, that, by a sudden plunge 

 of an iron-rimmed towing-net, half the cubic con- 

 tents, from which all water had percolated, gener- 

 ally consisted of nothing but one thick gelatinous 

 pulp. Each individual presented a minute yellow 

 digestive cavity, of the size of a millet-seed, which 

 contained Diatomaceae, Foraminifera, and other 

 organic particles. 



"If we take into account the numbers of Diato- 

 maceae and Foraminifera that must exist in order 

 to afford even a small integral proportion of the 

 diet of these creatures, the vast renewal of supply 

 that must be perpetually going on, and the 

 equally vast multitude of these Diatom-consumers 

 that yield, in their turn, a source of food to the 

 gigantic Cetaceans and other large creatures of 

 the sea, — it becomes possible, in some measure, at 

 least, to form an estimate of the manner in which 

 the deep-sea deposits become accumulated."' 



The same observer has, with great ingenuity, 

 applied these facts to the solution of that much- 

 vexed question, the origin of the masses of flint 

 that are found in the chalk. Diatoms are found 

 in great numbers in these nodules, but the diffi- 

 culty was, how to account for their aggregation 

 in these irregular masses. This is solved by the 

 hypothesis that they are the excrement of 

 100 





