396 NOTES. 



190 See Lewes's charming " Studies of Animal Life." Doubtless an ex- 

 amination of all the strata of the earth's crust would disclose forms im- 

 mensely outnumbering all those at present known. And even had we every 

 fossil, we would have but a fraction of the whole, for many deposits have 

 been so altered by heat that all traces have been wiped out. Animal life is 

 much more diversified now than it was in the old geologic ages ; for several 

 new types have come into existence, and few have dropped out. 



191 Among the types characteristic of America are the Gar-pike, Snapping- 

 turtle, Hummers, Sloths, and Musk-rat. Many of our most common animals 

 are importations from the Old World, and therefore are not reckoned with 

 the American fauna; such as the Horse, Ox, Dog and Sheep, Rats and 

 Mice, Honey-bee, House-fly, Weevil, Currant-worm, Meal-worm, Cheese-mag- 

 got, Cockroach, Croton-bug, Carpet-moth, and Fur-moth. Distribution is 

 complicated by the voluntary migration of some animals, as well as by Man's 

 intervention. Besides Birds, the Bison and Seals, some Rats, certain Fishes, 

 as Salmon and Herring, and Locusts and Dragon-flies among Insects, are 

 migratory. 



192 When the cable between France and Algiers was taken up from a depth 

 of eighteen hundred fathoms, there came with it an Oyster, Cockle-shells, 

 Annelid tubes, Polyzoa, and Sea-fans. Ooze brought up from the Atlantic 

 plateau (two thousand fathoms) consisted of ninety-seven per cent, of Fora- 

 minifers. 



