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 laterally and behind, ..... Phtllomedtjsa. 

 Parotoid very thin or wanting ; tongue free ; inferior palpebra 

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

 hh. 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, ....... Htla. 



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



Tongue extensively free ; dilatations minute, palmation extensive 



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



ccc. 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 : 



4 



Triprion 



-"o 





Opisthodelphys Trachycephalus 



Phyllomedusa Nototrema Osteocephalus 



\ \ / 



\ \6 / 



Pithecopus Scytopis 



Agalychnis Ranoidea Dryomelictes 



19 



- 1 I 3 / 



Smilisca H y 1 a Acris 



/ I 8 XT 



y Chorophilus Hylella 

 / 



/ 50 



Thoropa 



* Type P. azureus; second species P. hypochondrialis {Hyla hypochondrialis Daudin). 

 t Includes Phyllomedusa dacnicolor Cope. 



