On the Rodentia of the Somerset Caves

Abstract

H aving recently examined the collection of Rodentia from the Somerset Caves in the Taunton Museum, I find that several of the specimens cannot be referred to species which have hitherto been considered members of the fauna cotemporary with the Mammoth ( Elephas primigenius ) in Britain. 1. 1. Genus Arvicola .—As usual, bones and teeth of one or the other of the closely allied species, or perhaps varieties, which are about the size of, and have a dentition similar to that of Arvicola amphibius , abound in the Somerset Caves; but they are all fragmentary, and, as the observed differences between these species principally depend on the proportions of different parts of the animals, and not upon differences of form of the parts themselves, it is useless with our present materials to attempt to determine to which of these forms the fossils belong; it will be convenient to class them, as hitherto, as the bones of our common Water-rat ( Arvicola amphibius , Linn.). 2. 2. Arvicola glareolus (Schreber)= pratensis (Baillon)= riparia (Yarrell), appears to be a rare cave animal. We have never met with but two jaws; one of them is from Hutton Cave, and is in the Taunton Museum. 3. We have met with several lower jaws the dentition of which is identical with that of Arvicola agrestis (Linn.); but the diastema between the molars and incisor is longer, and the lower jaw itself is straighter in this part than in the recent jaws with which we have compared it. In this the jaws approach Arvicola ratticeps (Blasius); but we do