4o() I'ltOr. HUXLEY ON THE CLASSIFICATION OF DIRDS. [Apr. 11, 



It is unnecessary to enumerate the arguments by which the close 

 affinity of the proper Passerine birds (which make up the great bulk 

 of the jEgithognathous section) may be demonstrated, as the emi- 

 nently natural character of this group is admitted by every one. 



In their cranial characters, the Swifts are far more closely allied 

 with the Swallows than with any of the Desmognathous birds, the 

 Swift presenting but a very slight modification of the true Passerine 

 type exhibited by the Swallow. No distinction can be based upon 

 the proportions of the regions of the fore limb ; since in all the 

 Swallows which I have examined* the manus and the antebrachium, 

 res})ectively, greatly exceed the humerus in length, though the excess 

 is not so great as in Cypselus. 



The modification commenced in the Swift is greatly exaggerated 

 in JEyotheles and Caprhnuhjus ; while we have almost a transition 

 to the Desmognathous structure in Nyctibius. 



But if palatine characters have the taxonomic value which the 

 facts just enumerated appear to indicate, it follows that the Droince- 

 oynathons structure, so dift'erent from what is to be seen in any 

 other Carinate birds, has as much value as the rest, notwithstanding 

 the small actual extent of the group in which it obtains. 



It thus appears that the Dromseognathous, Schizognathous, Des- 

 mognathous, and J^lgithognathous arrangements of the maxillary 

 and palatine bones, respectively, characterize divisions of the Cari- 

 natse, all the members of which are mutually affined in other re- 

 spects. And I propose to regard these divisions as suborders, and 

 to name them Drom.^ognath.*;, Schizognath.e, Desmognathjs, 



and yEciTHOGNATH^f. 



-f- The suborder Drom^ognath^, containing only one family, the 

 TinamidcE, admits of no subdivision into groups of larger extent than 

 families ; but the other three suborders are very extensive, and, I 

 think, may be so subdivided in an ap})roximately satisfactory manner, 

 though any definition of these subdivisions which can be ])roposed 

 at })resent must be regarded as provisional and open to extensive re- 

 vision as our knowledge of the details of ornithic organization widens. 



-i-The Schizognath^. In addition to their cranial characters, 

 the birds composing this suborder often want intrinsic muscles in 

 the lower larynx, and never possess more than one pair of them. 



With the exception of Podiceps, all the genera which have been 

 examined have two carotid arteries. 



Six groups of allied families are distinguishable in this suborder. 

 These mav be termed the Charadriomorph^, the Gerano- 

 MORPH^, the Cecomori'h.e, the Spheniscomorph^, the Alec- 

 toromorphjE, and the Peristeromorph^J. 



* Hirundo pacifica, H. riparia, H. rustica, H. urlica. 



t DronuEUs, the generic name for the cassowaries ; ffx<?w, to cleave ; Sec^ibs, 

 a Ijoiul; AlyiBos, a sparrow. 



X Xa|Of;('|0(os, a sea-lark, or i)lover; Teioai^os, a crane; Kiyt, agiill; Sp/teniscus, 

 a genus of penguins; 'AX^KToip, a cock ; llcptari^pd, a dove; /.lopcp)), form. 



