198 Mr. A. R. Wallace on the Natural Arrangement of Birds. 



The last possess the metallic plumage of the American Tro- 

 gons, and habits almost identical, while the bill is an approach 

 to that of a Kingfisher. The Motmots {Pinonitidce) are also 

 closely related to the Trogons, and may be considered as an off- 

 shoot of them, or of the Bee-eaters, parallel to the Jacamars. The 

 habits of all these birds, and of the small Eastern Kingfishers of 

 the genus Ceyx, are almost identical, and we think there can be no 

 reasonable doubt of the very close affinity of these five families. 

 The Rollers (Corflc/ac?«) are the next group whose affinities we have 

 to consider. These birds have for a long time been strangely mis- 

 placed among the strong-legged Crows and Grackles, whereas the 

 short legs (with the toes united in some genera), wide gape, 

 insect food captured on the wing, the nest in holes of trees or in 

 the earth, and the colour and form of the eggs, all bring them 

 close to the Bee-eaters, Motaiots, and Kingfishers, the two former 

 of which appear to be their most direct affinities. The struc- 

 ture of the skeleton, according to the best observers, confirms 

 this result, which may therefore be considered as well established. 

 We now arrive at the Capitonidce, or Puff Birds of S. America, 

 which, like the Trogons, have been often placed among the 

 climbing birds, from having their toes placed two and two. 

 They are, however, true sedentary birds, with habits exactly 

 analogous to those of the Jacamars, Bee-eaters, and Trogons. 

 Some, like the Tamatias, frequent the gloomiest and thickest 

 parts of the forest, where they sit motionless on some low branch, 

 and thence take short flights after insects. Others, like Monasa 

 and Chelidoptera, frequent more open situations, sitting on bare 

 branches often of dead trees, and take longer flights, which in 

 Chelidoptei'a almost vie with those of Swallows for ease and 

 rapidity. The last-mentioned genera make their nests in holes 

 in sloping ground on the banks of streams, — a habit exceedingly 

 general among Fissirostral birds, but we believe quite unknown 

 among the Scansores. Their nearest affinities seem to be with 

 the Meropida and Tj-ogonidae, though their large heads and heavy 

 bodies would show some approximation to the Kingfishers. 



We now arrive at some birds which have always been asso- 

 ciated with the present group, of which, in fact, they appear to be 

 the highest development, but which are nevertheless widely sepa- 

 rated from the families we have hitherto been considering. 

 They are the Swallows and Goatsuckers. In these the power 

 of capturing insects on the wing has reached its maximum. 

 The gape is enormously wide, the feet generally very short, 

 and the wings long and powerful. Even between the two there 

 is, however, a considerable hiatus ; but no one has ever doubted 

 that they are more nearly allied to each other than to any 

 other birds. The question then remains, to which family of the 

 Fissirostres are either of them allied ? Where is the link that 



