284 BITFONID^. 



6. Orbito-tympanic ridges much developed, swollen. 



Toes entirely webbed 51. asper, p. 313. ^ 



Toes not quite half webbed 52. celehensis, p. 313. — 



Orbito-tympanic ridge confluent with the 



parotoid 53. galeatus, p. 314. — > 



2. A parietal ridge. 



a. Supero-orbital and parietal ridges forming together a 



straight or nearly straight line. 



Tympanum as large as the eye 47. hiporcatus, p. 311. 



Tympanum hardly two thirds the width 



of the eye; parietal ridges much 



swollen 48. daviger, p. 311. 



b. Supero-orbital and parietal ridges forming together an 



angle. 



Tympanum two thirds the width of the 

 eye ; tarso-metatarsal articulation 

 reaching beyond the tip of the snout . 49. divergens, p. 312. 



Tympanum two thirds the width of the 

 eye ; tarso-metatarsal articulation not 

 reaching beyond the tip of the snout . 50. parietalis, p. 312. 



Tympanum very small ; first finger shor- 

 ter than second; second and third 

 equal 61. dialophus, p. 319. 



II. Amekican Species. 



A. Cranial ridges none, or indistinct. 



1. Toes very slightly webbed. 



ITo tarsal fold ; tympanum small 9. debilis, p. 289. 



A thin tarsal fold ; skin smooth ; tarso- 

 metatarsal articulation reaching be- 

 yond the tip of the snout 10. hmnatiticus, p. 290. 



A rather indistinct tarsal fold ; tyibpa- 

 num two thirds the width of the eye ; 

 tarso-metatarsal articulation marking 

 the eye 11. guttatm, p. 290. 



A tarsal fold; tympanum hidden 13. cceruleostietus, p. 291. 



2. Toes one-third or half webbed. 



Skin perfectly smooth 12. glaberrirmis, p. 291."^ 



Tympanum scarcely perceptible ; a late- 

 ral dermal fold 14. diptyehus, p. 292. ^-^ 



Tympanum concealed ; lores vertical . . 16. monlcsim, p. 292. 

 Tympanum large, very distinct 17. mexieanus, p. 293. 



