:\1AMMALIA. 



67 



Among ]\Iyomorpha, it is interesting to notice that the Table-ease 

 lemmings [Mi/odcs Icmmvs and Cuniculus torquatus) occur in ^^• 

 the Pleistocene of England. There are also remains of a 

 large dormouse {Leithia melitcnsu) found with the pigmy 

 elephants in the caverns of ]Malta. 



Fig. 63. — Left upper (A) and light loweL ^B) teeth of Beaver {Castor fiber), 

 from the Fens of Cambridgeshire ; nat. size. 



Among Hystricomorpha, a skull of the gigantic CastorokJcs 

 ohioticvs from the I'leistocene of North America is shown ; 

 and there is a drawing-of a complete skeleton of this animal, 

 natural size, on the adjacent wall. There are also remains 

 of various genera from South America, where the extinct 

 Pleistocene Mega my s must som.etimes have l)een as large as 

 an ox. 



The Lagomorpha, or rabhits, picas, and hares, date hack 

 to the Oligocene period. 



Ordei; VII.— SIRENIA. 



The extinct representatives of the " sea-cows," so far as 

 known, ai'e very little different from the surviving meml)ers 

 of the Order. Discoveries in P'gypt merely suggest that 

 during the Eocene period they were most closely connected 

 with the early Proboscidean Ungulata. Various fossils 

 show that in Tertiary times they had a wider geographical 

 distribution than at the present day. 



Steller's Sea-cow {Rltytina f/if/as), which formerly browseil 

 on the sea-weed on the shores of Bering Strait, lived until 

 17ft2, when it was exterminated bv the Pussian sailors who 



F 2 



Pier-ease 

 29 (30). 

 Case V. 



