70 OSCINES, SINGING BIRDS. 



wards or even sideways ; its claw is as long as, or longer than, the claw of the 

 middle toe. The feet are neyer zygodactyle, nor syndactyle, nor semipalmate, 

 though the front toes are usually immovably joined to each other at base, for a 

 part, or the whole, of the basal joints. Various as are the shapes of the wings, 

 these members agree in having the great row of coverts not 

 longer than half the secondaries ; the primaries either nine 

 or ten in number, and the secondaries more than six. The 

 tail, extremely variable in shape, has twelve rectrices (with 

 certain anomalous exceptions). The bill is too variable to 

 furnish characters of groups higher than families ; but it is 

 alwaj's corneous, either wholly or in part, is never largely 

 membranous, as in many w^ading and swimming birds, nor 

 cered, as in birds of prey. No Passeres are known to have 

 riG. 12. Passerine foot, more than one common carotid arterj' ; and they all have the 

 sternum cast in one particular mould, with slight minor modifications of shape. 

 They are the typical Insessores, as such representing the highest grade of develop- 

 ment, and the most complex organization, of the class. Then- high phj'sical 

 irritability is coordinate with the rapidity of their respiration and circulation ; they 

 consume the most oxj'gen, and live the fastest, of all birds. They habitually reside 

 above the earth, in the air that surrounds it, among the plants that with them adorn 

 it ; not on the ground, nor on " the waters under the earth." 



Passeres, corresponding to the Insessores proper of most ornithologists, and 

 comprising the great majoritj'^ of birds, are divisible into two groups, commonly 

 called suborders, mainly according to the structure of the lower larynx. In one, 

 this organ is a complex muscular vocal apparatus ; in the other the singing parts 

 are less developed, rudimentary, or wanting. In the first, likewise, the tarsus is 

 normally covered on either side with two entire horny plates, that meet behind 

 in a sharp ridge ; in the other, these plates are subdivided or otherwise differently 

 arranged. This latter is about the only external feature that can be pointed out 

 as of extensive apiDlicability ; and even this does not always hold good. For 

 example, among our birds, the larks (Alaudidoe), held to be Oscine, and certainly 

 to be called songsters, have the tarsus perfectly scutellate behind. 



Suborder 080INES. Singing Birds. 



The first and higher of the two suborders just indicated. All of the birds com- 

 posing it have a more or less complex vocal apparatus, consisting of five pairs 

 of muscles ; but many of them do not sing. 



It is a question, which one of the numerous Oscine families should be placed at 

 the head of the series. Largely, perhaps, through the influence of those orni- 

 thologists who hold that fusion of the tarsal envelope into one continudus plate 

 indicates the acme of bird-structure, the place of honor has of late been usually 



