3884 NOTES. 
217 See Lewes’s charming ‘Studies in Animal Life.”’ Doubtless an exam- 
ination of all the strata of the earth’s crust would disclose forms immensely 
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. 
218 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-maggot, 
Cockroach, Croton-bug, Carpet-moth and Fur-moth.—Distribution is com- 
plicated 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. 
219 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. 
220 Only around the shores of the Arctic Sea are the same animals and 
plants found through every meridian ; and in passing southward, along the 
three principal lines of land, specific identities give way to mere identity 
of genera; these are replaced by family resemblances, and at last even the 
families become in a measure distinct, not only on the great continents, but 
on the islands, till every little rock in the ocean has its peculiar inhabitants. 
