General Remarks on the Classification of the Passerines. 49 



Thmnnopliilns, the Oven-birds, and their allies. The azygos carotid, from Nitzsch's 

 own results, appears in so many of his Picarii, that I think it may be passed over ; and 

 I have already spoken of the complete valuelessness of the differences observed in the 

 sternum. 



But the separation of the larynx into two chief forms cannot be accurately carried out. 

 The larynx of Cliamarhynclius has not its like in all the rest of the Passerines ; it shares, 

 at the same time, in the characteristics of the Ficarii and the Oscines ; according to its 

 foot and habits it would belong to the Ampelidae ; the muscles of its larynx act on 

 the whole breadth of one ring, as in some Tyrannidae, and at the same time on the 

 ends of a second ring, as in the Singing Birds; its muscular labium between the 

 larynx and the first half-ring is altogether peculiar. The larynx of the Parrots with 

 only a single glottis and three muscles, is just as peculiar. If the number of the 

 anterior and posterior muscles of the Singing Birds is reduced in Maenura, there are 

 also, even among the Picarii, examples of the single lateral muscle having an inclination 

 to become divided into an anterior and a posterior portion, as in Pipra leucocilla, while 

 it is undivided in the other Piprae. Among the Tracheoptiones the muscle of the larynx is 

 sometimes single {ThamnopJiilus, Mi/iothera, and Cfiamaeza), sometimes double {Furnarim, 

 Synallaxis, Bendrocolaptes, and others). If one can imagine the anterior and posterior 

 muscles of Maemira to be broadened, we should get a single mass of muscle, as in 

 Chasmarhpichus ; and if, on the other hand, the muscles of Cliamnarhynclms were divided 

 in the middle, and the first ring had the same relations as the second, we should get 

 the same muscular organ of voice as in the Oscines. Some of the Picarii differ from the 

 general type, inasmuch as their muscle is no true lateral muscle, but acts on the ends 

 of one ring ; thus, the large muscle of TrocJdlns, wliich covers the anterior face of its 

 larynx, only moves the posterior end of the second ring, and, from the posterior end of 

 this ring there goes, in the opposite direction, a second small muscle, which I was the 

 first to describe, to the succeeding rings, and which binds the half-rings together; of 

 such a form no other example is found either in the Oscines, or in the Picarii. The 

 muscular supply of the larynx in Colius is also peculiar, inasmuch as the lateral muscle 

 of the larynx is divided into bundles for several half-rings ; a condition which is quite 

 unusual among the Picarii. 



Finally, there are some Passerines which, notwithstanding the differences of their 

 larynges, are remarkably like one another. I will not speak of the Muscicapidae of the 

 Old and New World, which may be separated, as is already known, by the structure of 

 their feet and wings, since it is only in the Tyrannidae that the foot is granulated, 



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