﻿108 
  INTRODUCTION. 
  

  

  than 
  the 
  width 
  of 
  the 
  mouth 
  ; 
  tail 
  acutely 
  

   pointed, 
  at 
  least 
  nearly 
  twice 
  as 
  long 
  as 
  

   the 
  body 
  . 
  . 
  . 
  . 
  B. 
  esculenta. 
  

  

  Interocular 
  space 
  but 
  little 
  wider 
  than 
  the 
  

  

  distance 
  between 
  the 
  nostrils 
  or 
  the 
  width 
  

  

  of 
  the 
  mouth 
  ; 
  tail 
  once 
  and 
  two-thirds 
  to 
  

  

  twice 
  as 
  long 
  as 
  the 
  body 
  . 
  R. 
  arvalis. 
  

  

  h. 
  Series 
  of 
  labial 
  teeth 
  ^-f-^. 
  

  

  a. 
  Tail 
  obtusely 
  pointed, 
  once 
  and 
  a 
  half 
  to 
  

   twice 
  as 
  long 
  as 
  the 
  body. 
  

  

  Second 
  series 
  of 
  upper 
  labial 
  teeth 
  widely 
  in- 
  

   terrupted 
  in 
  the 
  middle 
  ; 
  first 
  series 
  of 
  

   lower 
  labial 
  teeth 
  at 
  least 
  two-thirds 
  the 
  

   length 
  of 
  the 
  second 
  ; 
  width 
  of 
  mouth 
  a 
  

   little 
  less 
  than 
  the 
  interocular 
  width, 
  

   which 
  equals 
  about 
  once 
  and 
  a 
  half 
  the 
  dis- 
  

   tance 
  between 
  the 
  nostrils 
  . 
  JR. 
  temjporaria. 
  

  

  Second 
  series 
  of 
  upper 
  labial 
  teeth 
  continuous 
  

   or 
  narrowly 
  interrupted 
  ; 
  first 
  series 
  of 
  

   lower 
  labial 
  teeth 
  at 
  least 
  two-thirds 
  the 
  

   length 
  of 
  the 
  second; 
  width 
  of 
  mouth 
  

   quite 
  as 
  great 
  as 
  the 
  interocular 
  space, 
  

   which 
  equals 
  about 
  once 
  and 
  a 
  half 
  the 
  

   distance 
  between 
  the 
  nostrils 
  . 
  B.grdeca. 
  

  

  Second 
  series 
  of 
  upper 
  labial 
  teeth 
  widely 
  in- 
  

   terrupted 
  in 
  the 
  middle; 
  first 
  series 
  of 
  

   lower 
  labial 
  teeth 
  hardly 
  half 
  as 
  long 
  as 
  

   the 
  second 
  ; 
  width 
  of 
  mouth 
  much 
  less 
  

   than 
  the 
  interocular 
  space, 
  which 
  equals 
  

   nearly 
  twice 
  the 
  distance 
  between 
  the 
  

   nostrils 
  . 
  . 
  . 
  . 
  . 
  B. 
  iberica. 
  

   j5. 
  Tail 
  acutely 
  pointed 
  or 
  submucronate, 
  

   at 
  least 
  nearly 
  twice 
  as 
  long 
  as 
  the 
  

   body. 
  

  

  Interocular 
  space 
  once 
  and 
  a 
  half 
  the 
  width 
  of 
  

   the 
  mouth 
  or 
  the 
  distance 
  between 
  the 
  

   nostrils 
  ; 
  no 
  tubercle 
  on 
  the 
  upper 
  man- 
  

   dible 
  . 
  . 
  . 
  . 
  . 
  B, 
  latastii. 
  

  

  Interocular 
  space 
  at 
  least 
  twice 
  the 
  width 
  of 
  

  

  