The number of plates or cylinders which compose the eyes of insects, a higher and more gifted class, differs in different species, amounting in the ant, so provident and wise, to only fifty, in the house-fly to eight thousand, and in the mordella to the amazing number of twenty-five thousand and eighty-eight. And yet how much is all this surpassed by the astounding mechanism displayed in the eye of the cod-fish, in whose crystalline lens there have been detected about five million fibers, every fiber containing about twelve thousand five hundred teeth; and the total number of these teeth or processes reaching the numerical, though to us utterly inconceivable, amount of sixty-two billions five hundred thousand millions! But more than all this. Look at the multiplied appliances furnished to the humblest and lowest of all living creatures for performing the functions of an existence scarcely removed above the vegetable. “The tentacula of polypi,” says Dr. Roget, “are exquisitely sensible, and are frequently seen, either singly or altogether, bending their extremities toward the mouth, when any minute floating body comes in contact with them. When a polypi is expanded, a constant current of water is observed to take place, directed toward the mouth. These currents are never produced by the motions of the tentacula themselves; but are invariably the effects of the rapid vibrations of the cilia placed on the tentacula. Now, of these organs a single _flustra foliacæa_ has been calculated to possess about 400,000,000.” Thus much for the Zoophyte class of animals—placed on the extreme verge of organized bodies—and members of a system of being, according to the development theory, whose primitive productions are of the simplest kind, the monads of a germinating vesicle!