RODENTS. 79 



canine teeth, and only a few molars, separated from the incisors 

 by a wide space. The species of the Swiss Tertiary land are 

 distinguished neither in size nor by possessing a form different 

 from that of the present day. Species representing Swiss mice 

 and rats have not been found ; and the family of the true mice 

 (Muridae), which is now distributed over the whole world, is 

 wanting in the Swiss Miocene fauna. 



The families of the squirrels, hares, chinchillas, and beavers 

 are found in Miocene strata. A squirrel (Sciurus Bredai, 

 Meyer) which has been preserved at QEningen seems to have 

 resembled the species now living in Swiss woods. The genus 

 Brachymys, one species of which (B. ornatus, Meyer) has been 

 discovered near Vermes, appears also to belong to this family. 



The hare-like rodents (Leporida) are represented by the call- 

 ing hares (Lagomys), which differ from the true hares by their 

 shorter ears and the want of a tail. At present these animals 

 live in Southern Siberia, in Mongolia, and in North America, 

 and, like rabbits, construct their dwellings in the earth. They 

 collect great stores of dried plants, which they preserve in their 

 habitations. The Miocene species differ from the living ones in 

 some essential points, and form a peculiar group (Myolayus, 

 Hens.) which approaches the true hares. Two species are not 

 uncommon in the uppermost stage of the Miocene. One of 

 them (L. ceningensis, Meyer), which was a little smaller than a 

 rabbit, is found not only at CEningen, but also at Elgg, where it 

 was the most abundant mammal. The second species (L. Meyeri, 

 Tsch.) was only half as large as a rabbit, and possessed more 

 delicately formed feet and slenderer claw-joints than the former, 

 with which it agreed in other respects. It is found at CEningen 

 and Vermes. 



The family of the chinchillas (Lagostomida) is at present con- 

 fined to South America. They are animals of considerable size, 

 with large ears, small fore feet, powerful hind feet, and tails 

 furnished with long hairs. Their fur is very soft and silky. It is 

 remarkable that Switzerland possessed about four species of these 

 animals. Two of them (Archceomys chinchilloides and A. Lau- 

 rillardi, Gerv., from Aarwangen) are so nearly allied to the 

 Peruvian chinchilla (Lagotis chinchilla), which furnishes a highly 

 prized fur, that it is probably not correct to form a distinct 



