EXTERNAL CHARACTERS. 19 



orbital space at least as broad as the upper 

 eyelid 9. Bufo vulgaris. 



Toes at least nearly half webbed, with single 

 subarticular tubercles; a tarsal fold; fingers 

 very obtuse ; interorbital space narrower than 

 the upper eyelid . 10. Bufo viridis. 



Toes webbed at the base, with paired subarticular 

 tubercles ; a tarsal fold usually present ; inter- 

 orbital space narrower than the upper eyelid ; 

 hind limb not, or but slightly, longer than head 

 and body . . . . 11. Bufo calamita. 



IV. Tongue cordiforra, free behind; fingers and toes 

 dilated at the end into distinct disks ; fingers 

 webbed at the base; vomerine teeth between 

 the choana3 ; pupil horizontal (Hyltd^e). 



12. Hyla arbor ea. 



V. Tongue forked and free behind; pupil horizontal 



(RANIDiE). 



a. Vomerine teeth between or extending slightly 



behind the level of the choanse; interorbital 

 space not more than half as broad as the 

 upper eyelid . .13. Bana esculenta. 



b. Vomerine teeth extending behind the level of 



the choana3 ; interorbital space at least one- 

 half the width of the upper eyelid. 

 1. Tibio-tarsal articulation rarely reaching the 

 tip of the snout, and never beyond ; 

 distance between the dorso-lateral folds 

 five to seven times in the length from 

 snout to vent. 

 Inner metatarsal tubercle large, hard, compressed, 

 measuring one-half to two-thirds its distance 

 from the tip of the inner toe ; first finger 

 extending beyond second ; tibia shorter than 

 the fore limb . . . 14. Bana arvalis. 

 Inner metatarsal tubercle small, soft, oval ; first 

 and second fingers equal, or first extending 



