Page:Popular Science Monthly Volume 1.djvu/335

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MUSICAL MICE.

of all things; and that the religious sentiment may find a higher sphere in the belief that the Ultimate Power is no more representable in terms of human consciousness than human consciousness is representable in terms of a plant's functions.

Other parts of Mr. Martineau's argument I pass over as being met by implication in the above replies. I will now add only that, should any further explanation be required, I must postpone it until I am free from present special engagements.

MUSICAL MICE.

By Rev. SAMUEL LOCKWOOD, Ph. D.

THE study of geographical range is of extreme interest as affecting the life, forms, and functions of animals. In this way has come about that convenient division of the Monkey order into two great sections—the Simiadæ, or Old-World monkeys—and the Cebidæ, or New-World monkeys. And this distinction is based on differences easy to be understood. The monkeys of the Old World have their nostrils so nearly terminal, and so near to each other, and their teeth in sort and number so much like those of man, as to give them traits more human-like than those of the New World. They have also cheek-pouches, but none of them have prehensile tails. The New-World monkeys have their nostrils wide, lateral, and sprawling; they have more teeth than man has; they have no cheek-pouches; and with many the tail is prehensile. But does this law of geographical distribution, whatever it may be, affect "mice, and such small deer?" It does. A very large order is that known as the Rodents, or Gnawers, well represented by the squirrels and rabbits. These animals are all characterized by two chisel-shaped teeth in the front of each jaw. The order contains several well-marked families, and some six hundred species. Of these families, one is known as the Muridæ, which embraces the rats and the mice, and their allies. Now, it is interesting to know that the Muridæ, namely, the true rats and mice, as well as the monkeys, naturally divide into two geographical groups: the one called the Mures, or Old-World rats; and the other known as the Sigmadontes, or New-World rats. Each of these divisions includes the true rats and mice, indigenous to the New and the Old World, respectively. And these distinctions are founded on a real difference in anatomical structure. Let it suffice to mention the most striking, that of the teeth. The Mures, or Old-World rats and mice, have comparatively "large, broad molars, and those of the upper jaw have three tubercles: the Sigmadontes, or New-World rats and mice, have narrow