CAMPYLORHYNCHUS. 9T 



There are some points of difference in different groups of Cavipij- 

 lorhynchus in the character of the nostrils and some other features. 

 In the type, as remarked, the nasal scale is reduced to a mere ridge 

 on the upper side of the nasal groove — the cavity being oval. In 

 jocosus it is similar, with the cavity more linear. In megalopterus, 

 ornatus, hrunneicapillus, and their allies, the scale is more developed, 

 as in tropical Wrens. In G. capistratus, rufinucha, humilis, etc., the 

 nostril is more like Donacobius and Heleodytes, namely, at the an- 

 terior end of the nasal groove, bordered behind by membrane, and 

 not above. In these the tail is shorter and less graduated than in 

 the type. C. capistratus is placed by Cabanis under Heleodytes, on 

 account of its peculiarities of nostril ; it differs, however, in shorter 

 tail, shorter bill, weaker legs, and the middle toe shorter than the 

 tarsus, not longer. 



The following table exhibits the peculiarities of the species before 

 me in reference to the nostrils : — 



A. Nostrils rather linear, horizontal, in lower side of nasal groove, and over- 



liung broadly by membrane thickened at edges : C hrunneicapillus, affinis, 

 pallescens, balteatus, megalopterus, zonatus, pardus. 



B. Nostrils more oval, the overhanging membrane reduced to a ridge on upper 



edge of nasal groove : C. variegatus, brevirostrisy zonatoides, jocosus (nostrils 

 more linear), albibrunneus. 



C. Nostrils as in Heleodytes ; broadly oval or rounded, in anterior end of nasal 



groove, with thin membrane behind : C. capistratus, rufinucha, humilis. 



The transition, however, from one to another form, is very gradual, 

 and it is quite difficult to say, in regard to some species, whether they 

 belong more properly to one section or to another. Without more 

 specimens therefore at my command, I prefer to consider all as 

 identical generically. 



The following synopsis may aid in determining the Middle Ameri- 

 can species, and their nearest S. American allies, by their colors : — 



A. Upper parts uniformly brown, without bands or spots. 



Head and neck with whole under parts white . . C. albibrunneus. 



B. Top of head and post-ocular stripe reddish-brown ; back 



streaked longitudinally and linearly with white. All the 

 feathers beneath conspicuously spotted. Crissum and 

 flanks with rounded or elongated spots. Nostrils in- 

 ferior, linear, overhung by a scale. 



a. Spots much larger on throat and jugulum than 

 elsewhere. Inner webs of 2d-5th tail feathers 

 (between middle and outer feathers) black, except 

 at tips ......... hrunneicapillus. 



7 August, 1864. 



