406 Dr. J. Murie on the Motmots and their Affinities. 



Edwards* very explicit, but appears to regard the INlomotidse 

 as allied to the Bucerotides among the Syndactylinse. Rein- 

 hardtf locates Momotus ruficapillus immediately after Ceryle 

 (Kingfishers). SharpeJ, through Ispidina and Myoceyx, hints 

 linear connexion from the Kingfishers to the Todidse and Mo- 

 motidse. 



VII. Conclusions derivative from data given. 



Definitions of a tentative kind, whereby subdivision of the 

 family may be recognized seem to rae a difficult matter. In 

 short, as much as my research among the group enables me to 

 tender an opinion, the Motmots barely admit of such a thing as 

 stable genera, so intertwined are their structural relations. 

 Regarding figure of the beak, as Plate XV. shows, the gradation 

 from the narrow to the broad variety is the reverse of sudden. 

 The magnitude of the mandibular serrations almost bears a ratio 

 to the size of the bird. The length of the tail-feathers from one 

 form to another is a series from shorter to longer ; even the 

 possession of a racket to the tip of the elongate median rectrices ■ 

 of some is deemed to be but a question of moult and age of the 

 bird. Thus the main differentiation to be depended on is ten 

 rectrices in some and twelve in others. Plumage, as part and 

 parcel of the tegumentary appanage, is notoriously subject to irre- 

 gularities of development dependent on a variety of secondary 

 causes. This circumstance, especially, weighs, as but a modicum 

 of information is known respecting the frequency and succession 

 of changes induced during moult and age in the Motmots. 



I have already intimated that Baryphthengus compared with 

 Momotus has no skeletal or organic character other than devia- 

 tion in its tail-feathers ; and this anomaly pertains to Urospatha. 

 The assumed more dilate and finer-toothed beak of Hylomanes 

 is one of slight degree, not kind ; whether its osteology may 

 offer singularity is dubious, reasoning from the similarity of 

 structure in the other forms. Proceeding to the two other as- 



* Oiseaux Fossiles, torn. ii. p. 300. 



t Bidrag til Kimdskab om Fuglefaunaen i Brasiliens Campos. Copen- 

 hagen, 1870. 



\ Map of the Family Alcedinidje, in his Monograph of that group. 



