American Species of Iv ma. 409 



or eye ; heels meeting^ or narrowly sepfl- 

 rated ; tibia 2| to 2J times in length 

 from snout to vent ; web extondin-j to 

 tip of fourth toe ; no dorso-latenil fold . li. grylio, Stejn. 

 Vomerine tooth on a level with posterior 

 borders of choana>, or just behind 

 them; first and second finpers equal; 

 tibio-tarsal articulation reaching i-ye ; 

 heels meeting or slifrhtly overlnppin<>'; 

 tibia 2 to '2\ times in length from snout 

 to vent ; one or two phalanj^es of fourth 

 too free; doi-so-liiteral fold present or 

 absent H, septcntrionalis, Baird. 



2. Male with internal vocal sacs ; dorso-lateral fold usually very 



distinct; vomerine teeth between choanre or just behind 

 them ; first finger as long as or a little longer than second ; 

 tibio-tarsal articulation reaching eye or between eye and tip 

 of snout; heels overlapping; tibia" 1^ to 2| times" in length 

 from snout to vent ; one or two phalanges of fourth toe 

 free. 



Uorso-lateral fold not extending beyond 



sacral region .".... li. clamitans, Daud. 



Dorso-lateral fold extending beyond sacral 



region li. onca, Cope. 



3. Male with external vocal sacs ; tympanum not larger than 



eye; first finger as long as or slightly longer than second ; 

 heels meeting or not. 



Head as long as broad ; tibio-tarsal articula- 

 tion reaching tympanum ; tibia 2j to 2§ 

 times in lengtli from snout to vent ; two 



fihalanges of fourth toe free ; no dorso- 

 atoral fold J?, virgatlpos, Cope. 



Head broader than long; tibio-tarsal arti- 

 culation reaching tympanum or eye ; 

 tibia 2 to 2 ', times in length from snout 

 to vent ; fourth toe webbed to the tip, 

 or la-<t phalanx free ; usually a more or 

 less distinct dorso-lateral fold R. montezuma^ Baird. 



B. Glandular dorso-lateral fold very distinct, extending to the hip 

 (exceptionally interrupted posteriorly) ; nasal bones widely 

 separated from each otner. 



1, Outer metatarsals separated nearly to the base ; toes obtusely 

 pointed, ^ to nearly entirely webbed ; tibio-tarsal articulation 

 reaching eye, tip of snout, or a little beyond ; tibia 3^ to 5^ 

 times as long as broad, \\ to 2^V times in length fi-om snout 

 to vent. 



a. Male with vocal sacs. 



Head as long as broad or a little broader or 

 a little longer ; interorbital space much 

 narrower than upper eyelid; dorso- 



