20 INTRODUCTION. 



slightly beyond second ; tibia as long as or 

 slightly shorter than the fore limb 



15. Rana camerani. 

 Inner metatarsal tubercle small, soft, oval; first 



finger extending beyond second ; tibia con- 

 siderably shorter than the fore limb 



16. Rana temporaria. 



2. Tibio-tarsal articulation reaching the tip of 

 the snout or beyond ; tibia nearly as long 

 as the fore limb; distance between the 

 dorso-lateral folds contained four to five 

 and a half times in the length from snout 

 to vent. 



a. Tympanum not more than two-thirds the 



diameter of the eye, distant from it. 



Distance between the nostrils greater than the 

 interorbital width ; first and second fingers 

 equal, or first extending slightly beyond second; 

 inner metatarsal tubercle nearly half the length 

 of the inner toe, as long as the diameter of the 

 tympanum . . . 17. Rana grseca. 



Distance between the nostrils greater than the 

 interorbital width ; first and second fingers 

 equal, or first extending slightly beyond second ; 

 inner metatarsal tubercle one-third the length 

 of the inner toe, shorter than the diameter of 

 the tympanum . . 18. Rana iberica. 



Distance between the nostrils not greater than 

 the interorbital width ; first finger extending 

 beyond second; inner metatarsal tubercle one- 

 third the length of the inner toe, shorter than 

 the diameter of the tympanum 



19. Rana, latastii. 



b. Tympanum two-thirds to five-sixths the 



diameter of the eye, and close to it ; 

 first finger extending beyond second ; 

 inner metatarsal tubercle very promi- 

 nent, but moderately large. 



20. Rana agilis. 



