94 ON THE STRUCTURES AND DISTRIBUTION OF THE 



aaa. ]^o cuneiform shovel or postorbital arch ; cephalic derm 

 not involved in ossification. 

 Prefrontals widely separated ; eyelids with dermal prolongation ; 

 vomerine teeth ; toes nearly free ; cranium elevated, form toad- 

 like ; inner finger not opposable, ...... Stombus.* 



Prefrontals in close contact ; eyelids not prolonged ; vomerine teeth 

 on palatine arch ; toes free ; cranium broad ; eyes subanterior, 

 pupil horizontal ; form squat, abdomen smooth, . . . ZACH^NUS.f 



Prefrontals not united, removed from the frontals; vomerine teeth; 



toes nearly free ; pupil vertical, ...... Limnomedusa.I 



? ? ? 



Prefrontals? eyelids simple; no vomerine teeth; toes free; eyes 



lateral, pupil horizontal ; form frog-like, ..... Natteeeria. 



Group III. Crini^. — Frontoparietal bones embracing a large fontanelle ; cephalic 

 derm free. Auditory apparatus developed, minute, or wanting. External 

 metatarsi bound, digits free, or rarely, webbed ; terminal phalanges simple. 

 Prefrontals never closely united, rarelj' in contact. Xiphisternum not dis- 

 tinguishable into style and disc, broad, emarginate, cartilaginous. Tongue 

 largely free. 



a. Ethmoid bone with superior arch complete ; a metatarsal 

 shovel ; toes margined or webbed. Vomerine teeth in 

 straight transverse series ; form stout. 

 Parotoid glands continued to groin and on dorsum; feet nearly 



free ; pupil round, . . . . . . . . . IIelioporus. 



No parotoid glands ; feet fully webbed, ..... Neobatrachus. 



No parotoid glands ; feet webless, ...... Platyplectrum. 



aa. Ethmoid arch complete ; no metatarsal shovel ; toes 

 J webbed; form depressed. 



I Auditory apparatus minute ; vomerine teeth ; xiphisternum with 



a proximal semiossified portion, ...... Cyclorhamphus. 



aaa. Ethmoid arch complete, or nearly so ; digits free ; no 

 cuneiform shovel. 

 Large parotoid glands ; no vomerine teeth, .... Hyperolia. 



No parotoid glands ; vomerine teeth in transverse series ; xiphis- 

 ternum broad, (with some basal bony deposit,) .... Borboroc^tes.§ 



* Type Ceratophrys boiei Wied. 

 t Type Cystignathus parvulus Girard. 

 % Type Cystignathus macroglossus Dum. and Bibr. 

 ? Includes Limnodynastes Fitz. Giinther 



