The _Shrew-Mice_ are still another kind of small ratlike quadrupeds. They are distinguished by having upon each flank, under the ordinary skin, a little band of stiff and close hairs, from which an odoriferous humour is distilled. They dig holes in the earth, which they seldom come out of until towards evening; and their food consists of insects and worms. A species that inhabits the Pyrenees, and also the mountains of Russia, are called Desmans, and differ somewhat from the ordinary shrew-mice. They are aquatic in their habits; and their burrows always enter the ground below the level of the water. The Russian species are usually termed Musk-rats; but these are not to be confounded with the musk-rats of America--which last should undoubtedly be classed with the beavers. In India, the shrew-mice attain to the size of ordinary rats, and are there also called musk-rats, from the fact that a strong odour of musk is exhaled by them--so strong as to make the place through which the animal passes exceedingly disagreeable. The same is true of the Russian musk-rats, but for all that their skins are employed in chests containing clothing: since the musky smell is a good preservative against the moths. In addition to the numerous rat animals above-mentioned, there are still other kinds in different parts of the world--the names of which would alone fill many pages. Hence it is that the study of this section of the mammalia is, perhaps, the most difficult of all; and a true classification of these small quadrupeds has hitherto proved a puzzle to the most expert zoologists. CHAPTER TEN. BEAVERS.