CHAPTER VIII. 



Suborder Clamatores, Non-melodious Passeres. 



The essential character that distinguishes this group from 

 the O seines, is purely anatomical, and consists in the non- 

 development of a singing apparatus. The vocal muscles of 

 the syrinx are small and weak, or consist of a large fleshy 

 mass not separable into individual muscles. This character 

 is somewhat uncertain in its determination, and probably 

 does not alwavs correspond with a certain condition of the 

 tarsal envelope which is seldom if ever observed in the 

 higher Passeres. The leg of a Kingbird being closely ex- 

 amined, will be found to be covered with a row of cylindri- 

 cal plates, which envelope the tarsus like a segmented scroll, 

 and which displays on its postero-internal aspect, a groove 

 of considerable depth, where the margins of the envelope 

 meet. This groove expands into a denuded space supe- 

 riorly, and is partly filled in, posteriorly, with a row of small 

 plates. This condition. w r ith some minor modifications, 

 characterizes the clamatorial birds. It differs somewhat tan- 

 gibly from the ordinary oscine tarsal character, in the presence 

 of entire lateral corneous plates, which meet in a sharp ridge, 

 posteriorly. Even when there is an extensive subdivision 

 of these laminae, both latterly and posteriorly, instance 

 Ampelis and Eremophila, the arrangement does not strictly 

 conform to the above description. The Clamatores repre- 

 sent the lowest Passeres, approaching, yet clearly separated 

 from Picarian birds. The families constituting the sub- 

 order are few in number. But a' single family is found in 

 North America, north of the Mexican boundary. 



