CETACEANS. 183 



are the most profitable months for cruising on the 

 Equator. 



Vast tracts of ocean may be cruised over without the 

 slightest trace of the Sperm Whale being perceived, 

 whilst other, and often very limited, extents of water 

 will exhibit the species in great abundance. Much of 

 this apparent caprice, however, depends upon natural 

 causes. Powerful currents, or the space intervening 

 between two currents setting in opposite directions, are 

 the favourite resorts of this whale, and, doubtless, 

 where its food is found in greatest abundance, amidst the 

 inhabitants of the deep swept together by these local 

 streams. Hence, wheresoever currents are denoted by 

 their concomitant marine animals, as the floating shell- 

 fish Janthina, Hyafaa, and Cleodora ; or other mollusks, 

 as Sea Lizards (Glaucus), Velell<B> Porpita, &c., with 

 myriads of medusae, forming what whalers term "thick 

 water," Cachalots may reasonably be expected; and 

 their appearance often coincides in a remarkable man- 

 ner with the presence of such natural indications. 



Nor is it difficult to conceive, that since the inhabi- 

 tants of the ocean, like those of the land, prey each 

 upon the other the smaller and less organized being 

 the food of the larger and more perfect animals so the 

 base of this column is formed by the mollusks, simple 

 in their structure, and much the sport of the element 

 they inhabit, and the capital by the cetacea, and the 

 largest or most rapacious fish. 



