as in the wild pigeons of America, crows, gulls, &c. The 

 number of Fishes which people the vast expanse of the ocean 

 may be judged of from the immense shoals of individual 

 species we frequently observe assembled together; as of 

 the cod, the herring, and many other species ; or from the 

 number of ova they produce at every period of spawning ; 

 upwards of 200,000 ova, for example, have been counted 

 in the spawn of a single carp, and more than 1,000,000 

 in that of the flounder. We frequently find our coasts 

 covered, for miles of extent, with a continuous and dense 

 layer of conchiferous or cirrhipedous animals, in a living 

 state, as with the mussel, the oyster, the barnacle; and 

 their debris accumulated, and thrown up by tides and 

 currents of the sea, form hills of shells, or are collected 

 into extensive beds, of some hundred feet in depth. The 

 distinguished Italian naturalist and traveller Donati 

 found the bottom of the Adriatic to be composed of a 

 compact bed of shells, crustaceous animals, and corals, 

 not less than six hundred feet in thickness. These 

 animals are infinitely more abundant on the tropical 

 shores of the New World, and the vast deposits of 

 them found in the interior of the earth, show how ex- 

 tensively they peopled the ancient seas. Myriads of Mol- 

 lusca and Conchifera live even beneath the sands of the 

 sea, as the Cardium, the Mactra, the Solen, the Mya, and 

 the Natica ; and the interior of the rocky strata are peo- 

 pled with living tribes of lithophagous animals ; as the 

 Pholas, the Teredo, the Petricola, and the Saxicava. The 

 moving hills of ants, the countries laid waste by locusts, 

 and the clouds of insects often observed, afford some idea 

 of the immense number of individuals which compose the 

 species of this class. Many Radiated Animals, as Medusa, 

 Actinia, and Asterw, are so numerous, that their carcasses, 

 accumulated on the shores of the sea, are employed to 

 manure the adjacent countries ; their abundance often 

 changes the colour of vast tracts of the ocean, or covers it 

 with a sheet of fire. The waters of the Arctic Seas and 



