326 



NORTHERN ZOOLOGY. 



FISSIROSTRES. 



The last division of the short-footed perching birds, which we have now arrived 

 at, comprises many groups, presenting- among themselves a great diversity of 

 structure, but all conspicuous for the weakness of their feet. Tn this respect they 

 resemble the Tenuirostres. There is, however, a remarkable difference in the 

 organization of the two groups, which is accompanied by habits no less dissimilar. 

 In the last assemblage of birds, the typical distinction rests upon the nourish- 

 ment being taken, or captured, by the tongue ; whereas among the Fissirostres 

 this office is performed only by the bill. The whole of these birds, in short, 

 however different they may appear to a superficial observer, agree in having a 

 very wide rictus or gape, always broad at its base ; their food, also, is no longer 

 vegetable, but is derived entirely from the insect world, and is caught during flight 

 in the manner of Swallows, — that family, in short, which stands pre-eminently 

 typical of the whole. The distinguishing characters of all these groups maybe 

 thus stated : — 



1. Typical group. 



Bill short, triangular ; rictus smooth ; feet perfect ; 

 plumage compact. 



2. Sub-typical group. 



Bill short, triangular ; rictus bristled ; feet im- 

 perfect ; plumage lax. 



3. Aberrant group. 



Analogies. 

 CONIROSTRES. 



Dentirostres. 



Families. 

 HlRUNDINIDJE. 



Caprimulgid^. 



ScANSORES. 



Tenuirostres. 

 Fissirostres. 



Bill stronger and longer ; feet short, imperfect, 

 and of different constructions. 



I 



Trogonid^. 



HaLCYONIDjE. 

 MEROPIDiE. 



So little has been published on the natural economy of the Trogons, that 

 hitherto our systematists have been left completely in the dark as to their pro- 

 bable station in nature. On this point we hope to communicate some interesting 

 facts, the result of personal observations on these birds in tropical America, in 

 another place. For the present, we shall merely premise that, as fissirostral birds, 

 they seize their food during flight ; that, as connected to the crepuscular Goat- 

 suckers, they feed chiefly during the evening; that, as united to Nyctyornis, Sw., 

 and Prionites, 111., the bill is either smooth or serrated ; that, as allied to the 



