American Species of Rana. 41 1 



ropion feebly oblique ; tibio-tarsal arti- 

 culation reacbing eye ; tibia 4J to 5 



tiiiiL's as Ion;,' aa broiul, li| to 2^ tiniea 



iu lengtb from euoiit to vont ; toes | 



webbed ; male witbout vocal sacfi .... li. yodmani, Gtbr. 

 Head very large, as long as broad or a little 



broader than long, '21 to 'A times iu 



length to vent; Inrenl region very 



oblique ; tibio-tarsal articulation reach- 

 ing anterior border of eye or between 



eye and nostril ; tibia 4 to 5 times as 



long as broad, If to nearly 13 times in 



length from snout to vent; toes ^ 



webbed ; male with external vocal sacs , R. arcohita, B. & G. 

 Head very large, much broader than long, 



2{ to 2S times in length to vent ; loreal 



region very oblique ; tibio-tarsal articu- 

 lation reaching tympanum or eye ; tibia 



3 to SA times as long as broad, '2 to 2| 



times in length from snout to vent ; 



toes ^ webbed ; male with external 



vocal sacs i?. capito, Leconte. 



II, Toes ending in very small discs; outer metatarsals separated 

 nearly to the base ; interorbital space equal to or a little less than 

 breadth of upper eyelid ; nasal bones widely separated from each 

 other. 



A. Loreal region moderately oblique ; toes entirely webbed or two 

 phalanges of fourth free. 



1. Tips of fingers swollen; vomerine teeth behind level of 

 choanaj ; tympanum \ to |; diameter of eye ; tibio-tarsal 

 articulation reaching tip of snout or beyond ; head broader 

 than long. 



No dor.so-lateral fold ; tympanum distinct ; 



heels not overlapping; tibia Ij to 2 



times in length from snout to vent ; no 



outer metatarsal tubercle; male without 



V( ical sacs R. tarahumaree, Blgi\ 



Dorso-lateral fold, if distinct, very broad and 



flat and restricted to the anterior half of 



tlie body ; tympanum feebly distinct, 



ill-detined; heels overlapping; tibia If 



to 1 J times lu length from snout to vent ; 



an outer metatarsal tubercle ; male with 



internal vocal sacs R. boylii, Baird. 



A moderately prominent dorso-lateral fold, 



extending to the hip, its distance from 



its fellow, on the back, .3.^ times in length 



from snout to vent ; tympanum very 



distinct; heels overlapping; tibia IJ 



times in length from snout to vent; no 



outer metatarsal tubercle li, pmtuiosa, Blgr. 



