Mr. A. R. Wallace on the Natural Arrangement of Birds. 197 



ganization ; and it is a remarkable proof of how little importance 

 is the form of the bill alone as an index of affinity, that in this 

 highly natural group we find every form of bill, — conical, 

 toothed, hooked, serrated, spear-shaped, curved, and flat. The 

 external characters which distinguish these birds are, very short 

 and weak legs, long, or at all events powerful wings, and a wide 

 gape. Their characteristic habit is to sit motionless, watching 

 for their prey, to dart after it and seize it on the wing, and to 

 return to their original position to swallow it. The groups which 

 possess these peculiarities in the greatest perfection are the 

 Trogons and the Kingfishers, with which we shall commence 

 our inquiry into the extent of the tribe. We must observe at 

 starting, that many continental ornithologists still place the 

 Trogons among the Climbers, because they have their toes 

 placed two and two, whereas those of the Kingfishers are 

 arranged as in the majority of birds. But this is a point of 

 detail which does not in the least affect the habits, for the toes 

 are in both cases connected together at their basis so as to form 

 a broad sole, giving a firm support to the bird without grasping. 

 In both the leg is equally short and weak, and in both all the 

 habits dependent on the feet are precisely similar. Of how very 

 little importance this change in the position of the toes is, unac- 

 companied by a change in their form, motion, or mode of con- 

 nexion with each other, we may judge from the fact of there 

 being species of Kingfishers and of Woodpeckers with only 

 three toes, and which yet have no perceptible difference of habits 

 from the rest of the family. It would be as reasonable (and as 

 unnatural) to withdraw these birds from their respective families 

 and form of them a new thrce-tocd family, as to separate the 

 Kingfishers from the Trogons for the reasons assigned. As an 

 instance how totally unable the Trogons are to use their feet for 

 anything like climbing, we may mention that the Trogons of 

 South America feed principally on fruit, which one would think 

 they would get by climbing or walking after if they could. But 

 no ; they take their station on a bare branch, about the middle 

 of the tree, and having fixed their attention on some particular 

 tempting fruit, they dart at it, seize it dexterously on the wing, 

 and return to their original seat. Often, while waiting under a 

 fruit-tree for Chatterers or Pigeons, have we received the first inti- 

 mation of the presence of a Trogon by the whir-r-r of its wings 

 as it darted after a fruit. It is curious that this habit seems con- 

 fined to the Trogons of America. In the East 1 have never yet 

 observed it, and in the numerous specimens 1 have opened 

 nothing has been found but insects. The African Trogons iilso 

 appear to be wholly insectivorous. 



Somewhat intermediate between the Trogons and Kingfishers 

 arc the Bec-eatcrs [Meropiike) and the .lacamars [Gnlhulkhe). 



