RODENTIA. 321 



forwards in the longitudinal direction, in correspondence with the 

 position of the transverse folds of enamel. Many of them build 

 nests, dig out complicated bin-rows, and lay up stores for the winter. 

 The latter usually possess cheek-pouches. Some fall into a dee]) 

 winter sleep at the cold time of the year, others migrate in large 

 flocks. They produce numerous young, some of them four or six 

 litters in the year, and possess, accordingly, a great number of 

 abdominal and thoracic mammae. Uterus usually completely divided ; 

 placenta discoidal. 



Fain. Leporidae. With long ears, powerful hind legs, and short tail. Den- 



1 o 5 1C,} r -2-2 0-0 3-3 3-3~l 



tition : _ ; c. p.m. /. - I. In the piaBmaxulse there 



1 :> L I'l 0-0 J 3-3 J 



are two posterior accessory incisors {J>n/>!iri/],'nt<ifa~). Li'pnx t'unirhis L.. 

 Hare; L. i-nrinliiUs Pall. Alpine hare; L. i-tmii-nl ux K.. Rabbit : Lu//<uf/x, Pikas. 

 L. i/tji//t,i/s F. Cuv.. barely a foot in lentrth. Siberia: L. prlm-i-px Richards. 

 Rocky Mountains. 



Fam. Subungulata. Grinders. -. The feet have naked soles, aud end in 



front with four, and behind usually with three toes. Cur in u/it-i-rii L.. Aperea, 

 in Brazil and Paraguay ; C. culm //a Schreb., the tame Guinea-pig ; Coelogenys paca 



L., the Paca, Brazil ; Dast/proctit m/titi I,., the Agouti : H;/dr<><-li<ri'tix rapi/bara 

 Erxl., the Capybara. four feet in length, the largest of living rodents. 



Fam. Aculeata. With short, obtuse snout, and spines on the dorsal side of 

 the body. CerculalH-s jn-eJiotxilin L., the Kuandu, Brazil : Ei'rfkizoit i 

 I... North America ; Jfi/xtri.r crixtritus L.. Porcupine, Italy and Spain. 



Fam. Octodontidae. 0<-t<lt>n Ci/initigii Benn., ( 'hili : Myopotamits 

 Geoff., the C'oypu. distributed from Brazil to Patagonia. 



Fam. Lagostomidae, Chinchillas. Eri<in/ Inni/jeru Benn.. the C'hinchilla 

 Chili ; Lar/i<Jhim Ciir/cri Wagn.; L/trjoxtonius h-ii-lioum-1 i/lnx Brookes, Viskatscha, 



Fam. Dipodae. Jerboas. With very long hind legs, which serve for jumping, 

 and large, usually tufted, jumping tail. Jm-iihix lulradorius Wagn.. Hiipt'maus ; 

 K .^ijt/ptiux Hemjir. Ehrnb.. Araln'a : D. xtnjitfu Scrn-eb.. Sea ,,f \ral : 

 ^x differ 111.. Cape jumping hare (Springhase), South Afiica. 



^ 



Fam. Muridae. Mice. Grinders: 1. With large eyes and ears, and long 



sometimes nairy. sumetimes ringed, scaly tail. Cricetus frumentarius Pall., 

 the Hamster; with internal cheek pouches ; constructs subterranean passages 

 and chambers, in which it accumulates winter provisions. It passes through a 

 short winter sleep, and is very hurtful to corn-fields. Jfux rtifti/x. L.. l!<>n^e-rat, 

 Black Hat : J/. flecumanitf Pall.. Grey Eat ; J/. iiuixci/liix L., House .Mouse ; 

 J/. tit i HH fits Pall. ' i>i'nil t'linifx) : Bydromys cJirysogaster (.Jeoffi-., Australia. 



Fam. Arvicolidae. Voles. With thick, broad head, rootless grinders, sliort. 

 hairy ears and tail. Arricola uiitphiliius L.. Water-rat : A. arriilix Pall.. Field- 

 mouse : .1. tit/ri-xfiij L. ; Hypiiilifiix r/titrrol HX Sehr. : Uli/mlrx li'iiuniix I... the 

 Lemming, on high mountains of Nm-way and Sweden, known by it-, migrations 

 in immense flocks before the apjiroach of the cold weather. Fiber zibet hi cut 

 L., North America. 



VOL. II. 21 



