[4] It will be well to bear in mind that when “rats’ bones” are mentioned, it must be understood that they are the bones, not of the common rat, but of the water-vole or water-rat. They are very abundant in Derbyshire barrows, and, indeed, are so frequently found in them, that their presence in a mound is considered to be a certain indication of the presence of human remains. “The barrows of Derbyshire, a hilly, almost mountainous, county, abounding with beautiful brooks and rills, inhabited by the water-vole, were made use of for its _hybernacula_, or winter retreats, into which it stored its provisions, and where it passed its time during the cold and frosty season. It is a rodent, or gnawer, or vegetable eater, and, as I have described elsewhere, has a set of grinding-teeth of the utmost beauty, and fitted most admirably for the food on which it lives. The part of the matter which is curious to the antiquary is, that the bones in Derbyshire barrows are frequently perceived to have been gnawed by the scalpri-form incisors of these animals. I have endeavoured to explain, in the note referred to, that all the rodents amuse themselves, or possibly preserve their teeth in a naturally useful state, and themselves in health, by gnawing any object that comes in their way. This is well known to every boy who keeps rabbits. I remember, some years ago, seeing a very fine black squirrel in the house of a workman in this town, which had been sent him by his son from Canada. It was found that it was impossible to keep this animal in any wooden house. He would gnaw a road out of the strongest wooden cage that could be made for him, in a few hours. In consequence, his owner made him a _tin cage_, in which he was kept securely. In confirmation of what I have said respecting the water-voles, vegetable feeders, gnawing the bones of the ancient Britons in barrows, I may refer to Linnæus’s most interesting _Tour in Lapland_. When in Lycksele, Lapland, June 1, he describes the _Kodda_, or hut of the Laplander, and incidentally remarks, “Everywhere around the huts I observed horns of the reindeer lying neglected, and it is remarkable that they were gnawed, and sometimes half devoured, by squirrels.”--I. 127. That is, if anything were truly devoured, it was the antlers, not the bodies. “The bones of the _Arvicola_, or water-vole, were found in the exploration of the colossal tumulus of Fontenay de Marmion, which was one of the galleried tumuli, opened in 1829, near Caen in Normandy. It belonged to the primeval period of the ancient Gauls.--Mem. de la Soc. des Antiq. de Normandie, 1831-3, p. 282.”--_Dr. Davis._ [5] See Note on the Distortions which present themselves in the crania of the Ancient Britons, by J. Barnard Davis, M.D., in the “Natural History Review” for July, 1862, page 290.