322 BULLETIN 34, UNITED STATES NATIONAL MUSEUM. 

 The natural genera are as follows : 



I. No teeth on the parasplieuoitl bone. 



1. Pupil horizontal. 



a. A frontoparietal fontanelle ; ethmoid not ossified above. 



Toes free Thoropa Cope. 



aa. A frontoparietal fontanelle ; ethmoid completed. 



Toes free, or nearly so; digital dilatations very small; sacrum little 



dilated Chorophilns Baird. 



Toes fully webbed; digital dilatations minute; sacrum little dilated. 



Jots D. & B. 



Toes webbed; digital disks and sacral diapophyses more dilated ; poUex 



consisting of one or more short concealed phalanges ; palpebra traus- 



parent , HtjUi Lanr. 



Like Hyla, but the dorsal derm introverted forwards, forming a sac. 



Notoirema D. & B. 



Like Hyla, but pollex consisting of phalanges fused into a curved solid 



exsertible spine ; palpebra transparent Hypsiboas Wagl. 



Like Hypsiboas, but palpebra reticulate with fibers Cmcloscopn^ C<i)ie. 



Like Hyla, but vomerine teeth wanting Utjlella K. & L. 



aa. No frontoparietal fontanelle. 



Derm of the head free ; no postfrontal process iScyiopis Cope. 



Derm of the head free ; a postfrontal process Smillsca Cope. 



Derm of front free ; bones exostosed Osleocepliahts Fit z. 



Derm of the head involved in the ossification ; no dermal sac. 



Traaliycephalus Tscli. 



Derm of head involved in the ossification ; a dorsal sac of the introverted 



skin Opisthodelphys Glhr. 



2. Pupil vertical. 



/i. No frontoparietal fontanelle. 



Tongue scarcely free behind; no digits opposable; cranial ossification 



involving derm Nyctimantis Bonl. 



j3/3. Frontoparietal fontanelle present. 



Tongue extensively free behind; sternum deeply emargiuate; digits not 



opposed when at rest ; cranial skin free Agalychnis Cope. 



Tongue extensively free; internal digits opposable, more or less free; 



sternu m entire ; cranial skin free Pliyllomedusa \N'agl 



II. Teeth on the parasphenoid bone. 



Pupil horizontal; vomerine teeth; cranial derm involved in ossifjcatioii 



of skull ; labial borders produced Diaglena Co])q, 



Vomerine teeth; toes webbed; derm of head involved in ossitication ;; 

 labial border produced ; pupil vertical Triprion Cope. 



In the series 1-2 lo Phyllomedusa a liiial duniuiition of palmatioii 

 accompanies continued size of the digital palettes and increase in the 

 length and breadth of the ethmoid and diminution of the frontoparie- 

 tals, which features, however, are as marked in Hijla palmata ns in 

 these succeeding types j they cany to its fullest development tlie cra- 

 nial peculiarities of the family, and add other features before men- 

 tioned; they inhabit the continental subregion of the Neotropical.. 

 The other main series (I-l) leads, first, to a fuller development of tbe 

 frontoparietals, then to an extension of the prefrontals, and hnally to 

 covering of the cranium with " dermo-ossiflcation," on the one hand with 

 the superaddition of a dorsal dermal sac, on the other without it. This 

 extreme finds its greatest expansion in the West Indian snbregion. A_ 



