264 Observations upon the Affinities 



dy intimated, affords assistance towards extricating the com- 

 ponent groups of the Insessores from the confusion into which 

 they have been plunged. The reader is referred, however, for 

 minute descriptions of the several modifications, to Mr. Yar- 

 rell's elaborate and well-known paper on the trachea of birds 

 in the 'Linnean Transactions.' The following are the varia- 

 tions presented in the present sub-class. First ; a wind-pipe 

 destitute of any peculiar muscle, which occurs only in the ge- 

 nus Sarcoramphus, (or condor, comprising Vultur gryphus 

 and V. papa of Linnaeus) ; the members of which are neces- 

 sarily deprived of voice, and emit no sound beyond a weak 

 snorting. Secondly ; the existence of a single pair of mus- 

 cles, which have been designated sterno-tracheales ; though 

 the term is not in every instance applicable, as in some birds, 

 (the crowned cranes, for example), the lower attachment of 

 these muscles is to the first true rib, and I have noticed some 

 other variations which require investigation : this, which is 

 the prevalent structure throughout the entire class, is com- 

 mon to the rest of the Accipitres, and to all other Insessores, 

 except the parrots, and those which have been indicated as 

 possessing small-sized coeca ; in the peregrine falcon, how- 

 ever, a. short second pair, or more strictly speaking division 

 of the first, is continued downward and attached to the bony 

 ring whence the bronchi divaricate ; and there are rudiments 

 of a similar structure in other species. We may generalize 

 by styling this a simple vocal apparatus. Thirdly; the com- 

 plicated inferior larynx of the Psittacidce, operated upon by 

 three pairs of muscles, and which is capable of dilatation and 

 contraction, whence the superior facility possessed by these 

 birds of inflecting the voice, and, by the more imitative, of 

 articulating words. Fourthly ; the complex organ of the ra- 

 ven, and its very numerous allies, presenting as many as five 

 pairs of muscles ; though in one instance, that of the mina 

 genus, (as I am informed by Mr. Yarrell), the long sterno-tra- 

 cheales being absent, the number is reduced to four.* All 

 singing birds appertain to this division ; and although many 

 species, framed upon the same rudimental type, and conse- 

 quently possessing similar vocal organs, as the cotingas and 

 manakins, and our native nuthatch, have only a monotonous 

 cry, yet the reason of this does not proceed from the incapa- 

 city of modulating the voice, as songless species, reared in 

 captivity under warblers, have been known to imitate the 

 notes of the latter to perfection. 



* This exception may be regarded as analogous to that which the con- 

 dors offer to the rest of the Accipitres ; all the peculiar muscles of the pre- 

 ceding group being retained. 



