406 ORDERS OF MAMMALIA. 



2—2 0—0 3—3 3 — 3 



i ; c ; pm ; m =28. 



1—1 0—0 ^ 2—2 3—3 



The clavicles are imperfect. The fore-legs are furnished 

 with five toes, and are considerably shorter than the hind- 

 legs, which have only four toes. The two orbits communi- 

 cate by an aperture in the septum. Generally there is a 

 sliort erect tail. 



The genus Lepus itself is found in the Pliocene deposits 

 of both North and South America, and in the Post-Pliocene 

 cave-deposits of Brazil occurs a Hare, nearly allied to the 

 living L. Brasiliensis. In the Miocene of North America the 

 Hares are represented by the extinct genus Falcvolagus, and 

 in the Pliocene of the same country we have the extinct 

 genus Panolax. Forms closely allied to, or actually be- 

 longing to, the genus Lepus have also been indicated as 

 occurring in the Miocene, Pliocene, and Post-Pliocene deposits 

 of Europe. 



Fam. 2. Lagomydm. — In the Calling - hares or Pikas 

 {Lagomys), which form this family, tlie legs do not differ 

 much in size, tliere is no visible tail, and the clavicles are 

 nearly complete. They are found in Paissia, Siberia, and 

 North America. 



The existing genus Lagomys is found as early as the 

 Miocene in France, and occurs also in the Pliocene of 

 Europe, while the Cave-pika is found in the Post-Glacial 

 deposits of Britain. The Titanomys of the French Miocene 

 differs from Lagomys chiefly in the possession of a lower 

 molar fewer (fig. G83, d). In the neighbourhood of the 

 Hares and Calling - hares we may provisionally place the 

 remarkable and aberrant Typothcrvum (or Mesothcrium) of 

 the Pliocene of South America, which presents affinities 

 both to the Toxodonts and the Ungulates, and which can- 

 not at present be definitely referred to any family of the 

 liodents. This singular form was larger than the existing 

 Capybara, and therefore possessed dimensions greater than 

 those of any living Eodent. It had clavicles, and the fore- 

 feet were pentadactylous, while the hind-feet had only four 

 toes. The dental formula is — 



