42 



On the Relations between the Structicre of the Organ of Voice, 



safety place among the Singing Birds those East Indian and Australian forms, whose larynx 

 has not yet been examined, but which are provided with the bilaminate tarsus ; as Ejumachis, 

 Pomaturhiniis, Pitta, Mj/iophonus, Padiycephala, Fregilus, Grallina, and Paradisea. 



(4) For the birds of the New World the conclusion, from the presence of the tarsal 

 scutes, that there exists a muscular organ of voice, does not hold. At any rate, there is 

 something very much like the tarsal scutes, where the hinder side of the foot, both internally 

 and externally, is devoid of either granules or plates ; and the larynx with several muscles 

 is absent. 



(5) In those birds on the hinder side of whose foot are two series of large plates, 

 no safe deduction as to the internal structure can be made, from their presence; indeed, 

 this structure of the foot may be allied with the most various forms of internal structure. 



(6) In South America this structure only appears in birds without the muscular 

 organ of voice, and iu particular, in .several TracheopUones. The European form of Singing 

 Birds with two series of plates behind, that is as iu the Larks, does not appear at all 

 in South America. What have been considered, in South America, as Larks, are partly 

 species of Furnarius, and partly of Ceiitrites (Cab.) The South American Passerines, therefore, 

 with two series of large plates on the hinder side of the foot, which meet one another 

 at its hinder edge, are to be placed by analogy with the already examined Chamaeza, 

 Thamnophilus, and Scytalopus, along with the Tracheojitiones, even if we do not know 

 the organ of voice, as in the cases of Mylochida Sw., and Pteroptoc/ius Kittl. 



(7) Where the anterior ))lates of the foot pass right round to the hinder edge, it 

 may be safely supposed that the larynx with many muscles is wanting, as in Kuipoleyus 

 and Fidomophagus. This never exists in company with the muscular organ of voice, but 

 has always been observed when it is absent. 



(8) Among the Trac/ieophones, whose larynx has been examined, there are genera 

 allied to one another, of which one has the foot covered with two series of plates, and 

 the other is without a horny covering on the external and internal parts of the hinder 

 side, and is, as it were, encased. The latter can be recognised from their allies. This 

 is the case, for example, with Pithys and Grallaria, which may very safely be supposed 

 to be Traclieoplimiei. Chamaczu bears the same relation to Grallaria, as Thamnopltilus to 

 Myiothera. 



(9) Among the Trachenphones there is a form of covering for the foot, which in 

 some genera cannot be accurately differentiated from that of the Picarii, and in others 

 from that of the true Singing Birds. 



In the following table I have put together those Passerines which want the larynx 



