472 RODENTIA 



expanded, with a corresponding reduction of the parietal and inter- 

 parietal, and the interorbital constriction of the frontals attains its 

 greatest development. Fossil remains of Fiber occur in the North 

 American Pleistocene. 



Neofiber. 1 — This genus, while agreeing with Fiber in the characters 

 of the skull and teeth, differs by the cylindrical tail, and the normal 

 form of the feet, in which the toes are not bent laterally at an angle 

 with the sole. The single species N. alleni, commonly known as 

 the Round-tailed Musk-Rat, is found in Florida, and is much less 

 completely aquatic in its habits than Fiber. Its colour is brown 

 above, and silvery-white mixed with rufous below, the sides of the 

 body gradually shading from brown to rufous, the forehead and 

 the tip of the nose are black, while the tail is rufous mingled with 

 black. 



Subfamily Siphneinse. — Includes two genera of Mole - like 

 Rodents with an Arvicoline dentition, but with the body thoroughly 



Fig. 210. — Siphncus armandi. (From Milne-Edwards.) 



adapted for a subterranean life, the limbs and tail being very short, 

 and the external ears rudimentary. Both are Palaearctic. 



Ellobiusr — The Russian F. talpinus, the typical representative 

 of the genus, has short claws, and comes nearest to the Arvicolince. 

 E. fuscocapillus is from Afghanistan. 



Siphneus. 3 — This genus (Fig. 210) includes species inhabiting 

 Northern and Central Asia, and is characterised by the great length 

 of the claws of the manus. Remains of an existing species occur 



1 True, Proc. U.S. Nat. Mus. vol. vii. p. 170 (1S84). 



2 Fischer, Zoognosia, vol. iii. p. 72 (1814). 



3 Brants, Het. Gcslact dcr Muizen, p. 20 (1827). 



