86 ON THE STRUCTURES AND DISTRIBUTION OF THE 



h. Posterior digits free, two opposed to three ; xiphisternum 

 entire; pupil vertical. 

 A large prominent paratoid ; inferior palpebra transparent ; tongue 



extensively free latei'ally and behind, ..... Phyllomedusa. 

 Parotoid very thin or wanting ; tongue free ; inferior palpebra 

 netted or transparent ; second toe shorter than inner, . . Pithecopus.* 

 bh. Posterior digits rarely opposable, pupil rarely vertical ; 

 xiphisternum deeply emarginate. 



c. Pupil vertical ; inner posterior digits more or less opposable. 

 Tongue elongate, extensively free laterally and behind ; inferior 

 palpebra latticed ; toes more or less webbed, second longer than 

 inner; sometimes thin parotoids, ...... AGALTCHNis.f 



cc. Pupil horizontal ; posterior digits webbed, not opposable. 



Tongue short, attached or little free ; palpebra usually trans- 

 parent ; vomerine teeth, ..-.•.. Hyla. 



Tongue short; palpebra transparent ; no vomerine teeth, . . Hylella. 



Tongue extensively free ; dilatations minute, palmation extensive 



behind ; vomerine teeth, ....... AcRis. 



ccG. Pupil horizontal ; posterior digits flat, free. 



Superior ethmoid plate osseous ; prefrontal bones separated, . Chorophilus. 



Superior ethmoid plate cartilaginous, the prefrontals developed, in 



contact medially, ......... Thoropa. 



The affinities of these genera are most readily exhibited by an arrangement like 

 the following : 



Triprion 



Opisthodelphys Trachycephalus 



2 \ 



Phyllomedusa ' Nototrema Osteocephalus 



\ \ ' / 



' Pithecopus Scytopis 



Agalychnis Rauoidea Dryomelictes 



- r = . 



Smilisca H y 1 a Acris 



Chorophilus Hylella 

 Thoropa 



/ 



/ 10 



* Type P. azureus; second species V . h y p o c h o n rl r i a I i s ( Hijln hi/p'irhnndrialis Daudin) 

 t Includes Phyllomedusa dacnicolor Cope. 



