410 Mr. G. A. Boulenger on the 



lateral folds narrow or moderately 

 broad, usually -with interrupted folds or 

 elongate waVts between them ; outer 

 metatarsal tubercle absent or very indis- 

 tinct ; male with external or internal 



vocal sacs H. halecina, L. 



Head as long as broad ; interorbital space 

 much narrower than upper eyelid ; 

 dorso-lateral folds very broad, with a 

 pair of similar folds between them ; 

 outer metatarsal tubercle usually pie- 

 sent ; male with internal vocal sacs . . R. palustris, Lecoute. 



h. Male without vocal sacs. 



Head broader than long ; interorbital space 



as broad as or narrower than upper eye- 

 lid ; tympanum § to once diameter of 



eye ; outer metatarsal tubercle absent 



or very indistinct R. draytonii, B. it G. 



Head as long as broad or slightly broader 



than long ; interorbital space narrower 



than upper eyelid ; tympanum f to ^ 



diameter of eye ; a more or less distinct 



outer metatarsal tubercle R. aurora, B. & G. 



2. Web not penetrating beyond basal half of outer metatarsals. 



a. Glandular dorso-lateral fold narrow or moderately broad ; 



head moderately large ; vomei'iue teeth on a level with 

 or behind posterior borders of choauoe. 



Tibio-tarsal articulation reaching tjonpanum 



or eye ; tibia 3 to 4^ times as long as 



broad, 2 to 2i times in length from 



snout to vent ; toes | to nearly entirely 



■webbed ; inner metatarsal tubercle \ to 



i length of inner toe; male without 



vocal sacs R. pretiosa, B. & G. 



Tibio-tarsal articulation reaching tympanum 



or eye ; tibia 3 to 4 times as long as 



broad, 2i to 2| times in lengthfrom snout 



to vent ; toes | to | webbed ; inner meta- 

 tarsal tubercle ^ to | length of inner toe ; 



male with internal vocal sacs R. cantahric/ensis, Baird. 



Tibio-tarsal articulation reaching beyond 



eye ; tibia 4 to o times as long as broad, 



If to 2 times in length from snout to 



vent ; toes f to | webbed ; inner meta- 

 tarsal tubercle | to 4 length of inner toe ; 



male with internal vocal sacs R. silvatica, Leconte. 



b. Glandular dorso-lateral fold broad ; vomerine teeth between 



the choanse. 



Head moderate, slightly broader than long, 

 3 to 3^ times in length to vent ; loreal 



