] 84 CTSTIGNATHID^. 



one of the highest degrees of cranial ossification which a Frog can 

 attain. 



The auditory organ exhibits all the possible degrees of develop- 

 ment. Several genera, viz. Crlnia, Hylodes, &c., prove that too 

 great an importance has been attached to the modifications of this 

 organ, and in most cases I miist refuse to admit them as generic 

 characters. 



The distal phalanges are simple, or with divergent terminal pro- 

 cesses. 



Most of the Australian representatives of this family, and a few 

 of the American, have the pupil erect. 



The Cystignathida' include arboreal, aquatic, terrestrial, and 

 burrowing types. 



Synopsis of the Genera. 



I. Outer metatarsals completely separated ; sternum without 



bony style ; toes webbed. 



Pupil horizontal : first finger opposite to the others ; tongue circular, 



1. Pseudis, p. 185. 



Fingers webbed : tips of fingers and toes dilated into large disks. 



2. Centrolene, p. 187, 



Pupil erect : tongue circular : tympanum distinct. 



3. Mixophyes, p. 188. 



Tongue oval : tympanum hidden . . 4. Cyclorhamphus, p. 189. 



II. Outer metatarsals united or incompletely separated. 



A. Sternum without bony style ; toes webbed. 



Pupil horizontal ; head rough, entirely bony, the orbit completely 

 enclosed ; tongue entire 5. Calyptocephalus, p. 189. 



Pupil horizontal ; derm of head free from cranial ossification ; 

 tongue entire 6. Telmatobius, p. 190. 



Pupil horizontal ; tongue nicked behind. 



10. Ceratophrys, p. 221. 



Pupil vertical ; first finger opposite to the others ; diapophyses of 

 sacral vertebra slightly dilated . . 23. CMroleptes, p. 207. 



Pupil vertical : tj-mpanum concealed ; diapophyses of sacral vertebra 

 slightly dilated 24. Heleioporus, p. 271. 



B. Sternum without bony style ; toes free, or nearly so. 



1. Tips of fingers and toes dilated into regular disks ; pupil 

 horizontal. 



Vomerine teeth ; digital disks divided on their upper surface by a 

 groove 7. Elosia, p. 193, 



