INTRODUCTION. XV 



A» PASSERES.* Ilalliix iiivarial>ly pivseni, compleU-ly incuinl'«'iii. scpii- 

 ratclv iiiovublo by sjK'<-iali/.:ition of tht* jlKi'ir halhicis Unujas. \vitli i.'iilai,La'(l 

 base and its claw latyr than that of llic niiddh' digit. Xi'ithtT second nor 

 tbnrtli toe versatile; joints of toes always '1, .'>. 4. '). from lirst to fourth. 

 Wing-coverts comparatively short and lew : with the exception of the Irast 

 coverts upon the ]tllcn alaris. airangeil in only two series, the greater of 

 which do«'S not 'each beyond the middle of the sccon.d;iry rcmiges.' Jiee- 

 triees twelve (with rare anomalous exeopti(.>ns). Musical apj»aratus present 

 in L'leater or less development and complexit}'. Palate a'githognathous. 

 Stermnn of one particnlar mould, smgle-notched. Carotid single (sinistra). 

 Xature highly altrii.'ial and ]>silopiedie. 



a. Oscines.^ Siiles of the tarsus covered in most or all of their extent 

 with two undivided horny plates meeting ojhind in a sharp ridge (ex- 

 cept in AhiHililce : one of the plates imperfectly divided in a few other 

 forms). Musical aj»paratus highly developed, consisting of several dis- 

 tinct pairs of syringeal mnsdes. Primaries nine only, or ten with the 

 first fre([nently spurious, rarely over two thirds the length of the 

 longest, never eunallinir the lonirest. 



b. Clamatores.* Sides of the tarsus covered with <livided plates or 

 scales variously arranged, its hinder edge l>lunt. Musical apparatus 

 weak and imperfect, of few or incompletely distinguished syringeal 

 muscles (as far as known). Primaries ten with rare exceptions, the 

 fust usually ecpialling or exceeding the rest. 



B. PICARTJE.^' Hallux inconsi<lerable, weak or Avanting. not always in- 

 cinnltent. not separately movable by <hst'nction of a special nujscle, its claw 

 not longer than that of the middle toe unless of exceptional shape (e. g. (^en- 

 tropiis). .Second or fourth toe frequently versatile; third and fourth fre- 

 quently with decreased mnnber of joints. Wing-coverts for the most part 

 larger anil in more immerous series than in Passeres, the greater series 

 reaching V)eyond the middle of the secondary quills (except in many Pici 

 and s(jme others). Rectrices commoidy ten (eight to twelve). Primaries 

 always ten, the first only excei)tionally short (.as in Pia'). Musical appara- 

 tus wanting, or consisting of a muscular mass, or of not more than three 

 pairs of svrinireal nniscles. Palate desmoirnathous or a'githosrnathous. 

 Sternum of non -passerine character, itis posterior border entire o • doubly 

 notched or fenestrate. Carotid single or douV>le. Nature completely al- 

 tricial, but young sometimes hatched with down' (e. g. Caprimidgid(E). 



|)o.ssess in connnon one single character not also to be found in other groups, nor is the colloca- 

 tion of their characters peculiar. 



1 CorresiKUKling closely with the Linniean and earlier Suudevallian acceptation of the term. 

 Kipiivalent to the later Osciiu\s of Sundevall. 



'^ As remarked by Sundevall, exceptions to the diagnostic pertinence of these two characters 

 of hind claw and wing-coverts taken together are scarcely found. For, in those non-^wsserine 

 birds, as Raptorcs and some ILrodiows, in which the claw is enlarged, the wing-covt'rts are 

 otherwise disposed ; and similarly when, as in many Piri and elsewhere, the coverts are of a i>as- 

 serine character, the feet are highly diverse. 



^ Lamin iplanta res o{^\\mV\A\\ \\\\% Aland iiJfr. 



* Scufellijdanf'irrn of Sundevall minus Alotidiihr. 



* Nearly equivalent to the Linuiean Pim\ Eipial to the late (1S73) Vnlucres of Sundevall. 



® A polymorphic group, ]u'rfectly distinguished from Pasarres by the above characters in which, 

 for the most part, it approximates to one or another of the following lower groups, from which, 

 severally, it is distinguished by the inapplicability of the characters noted beyond. My divisions 



