422 Analytic Descriptions of the Groups of Birds 



Lastly, the Heterodactyli require to be separated into those 

 with zygodactyle feet, (though on a different principle from 

 any of the preceding groups), — Trogonoides ; and with feet 

 not^ zygodactyle, — Cypseloides. The former contains only 

 the single family of trogons, {Trogonid<e), which may also be 

 termed Accurvirostres ; the latter consists of the Parvirostres, 

 or moth-hunter family, (Caprimulgidce), perhaps separable 

 into two sub-families, — and Tenuirostres, or the swifts, [Cyp- 

 selidce), and hummingbirds, {Trochilidce). 



The following tabular view exhibits the foregoing distribu- 

 tion of the successive groups of Strepitores at a glance. 



Syndactyli, 



Zygodactyli, 



Heterodactyli, 



Buceroides, 



Halcyoides, 



Picoides, 



( Buceridce. 

 \ Upupidce. 

 (MeropidcB. 

 (Cylindrirostres, j Coracidce. 



\ Arcuirostres, 



Angulirostres, 

 ^Serratirostres, 

 | Levirostres, 



{ Halcyonidce. 

 ( Todidce. 

 \ Galbulidce. 

 Prionitida. 

 { Rhamphastida. 

 \ Musophagidce. 

 j Bucconidce. 

 1 Picidee. 



Cuneirostres, 



~ 7 ., ( n j. { Tamatiadce. 



iCuculoides, \Curvuhrostres, \ CucuM ^ 



Trogonoides, Accurvirostres, 

 ' Parvirostres, 



Cypseloides, 



Tenuirostres, 



Trogonidee. 

 Caprimulgidee. 

 Cypselidee. 

 Trochilida. 



And a more striking contrast cannot be than is afforded by 

 this long succession of mutually distinct forms, as compared 

 with the next order, Cantores, which scarcely affords a sin- 

 gle character for subdivision, though containing, perhaps, tri- 

 ple the number of species at the lowest rough estimate. 



My last communication was devoted to the consideration 

 of the two syndactyle groups of Cylindrirostres and Anguli- 

 rostres ; and I will content myself, at present, with complet- 

 ing the Halcyoides, by treating on the Serratirostres, or 

 motmots. The Buceroides will form the subject of my next 

 paper. 



The family of motmots, — Prionitidce, called also sawbills, 

 and houtous, (which latter name expresses the unvaried cry 

 of one of the species), — is peculiar to the tropical regions of 

 South America, and combines several characters of the king- 

 fishers with others of the toucans. 



The species average the size of a small jay; and their pro- 

 portions resemble those of a common magpie. The foot is 

 syndactyle, yet moderately adapted for progression on the 



