14 PASSERES. 



to eaoli front toe. The Flexor Jongiis JutUucis arises from the 

 outer condyle of the i'enuir and from the intercondylar region. 

 It accompanies, and is closely associated with, the J'l. profundus 

 throngiiout its aa hole length. Passing also into the tendinous 

 condition at the intertarsal joint, it crosses the Fl. iirofundus 

 tendon near its middle, from behind and from without inwards 

 to be inserted on the lerminal ])halanx of tlie hind toe. 

 This, at least, is wliat obtains in all the Passeres save the 

 Farijlcemida'., where the liallucis tendon anchors itself to the 

 profundus tendon at the point where the two tendons cross, 

 by a number of tendinous fibres, to form wliat is Imown as a 

 " vinculum." No less than eight different modes of ancliorage 

 between these two tendons are recognized. Tlie typical Passeri- 

 form type is No. YII. of this series; that of the Ean/Icemidce is 

 No. 1/ 



Nitzsch, in laying the foundations of the study of the pterylosis, 

 opened up a field of great promise, which, so far, has only very 

 partially been explored by systematists. The attempt to use the 

 number of the remiges as a factor in the subdivision of the Passeres 

 lias oiilv resulted in the formulation of a test which is based on 

 error. Thus, in the previous edition of this work an attempt 

 was made to form two Groups of Passeres, the one displaying 9, 

 the other 10 primaries. This was uufortuuate, since all the 

 so-called " 9-primaried" Passeres possess lO remiges, while many 

 of the so-called " 10-primaried " Passeres jiossess 11 remigvs. 

 The error has arisen from a failure to distinguish vestigial quills 

 and their coverts. In tlie " 9-primaried " Passeres the lOlh may 

 be reduced to the vanishing point. AV^iiere the 10th primary is 

 conspicuously long, as in the Corvidse, the 11th will be found as 

 a '• remicle," 1 cm. or more in length. Bearing these facts in 

 mind, there can be no objection, for the sake of convenience, 

 to the continued use of the division into 9-prnnaried and 10-pri- 

 niaried wings, the remicle being in both cases a negligible 

 quantity. 



So far, unfortunately. Ornithologists have made no more use of 

 pterylosis than this numbering of the wing and tail-feathers. 

 A vast amount of work has yet to be done, in investigating 

 the ])terylosis of the trunk, for tlie sake of the evidence it will 

 unquestionably furnish as to the relationship of forms v\hose 

 affinities can at the present be no more tlian guessed at. The 

 ParidiH, AmjH'lidce, Oriolidce afford cases in point. True, we 

 cannot discover this evidence by a study of the pterylosis alone— 

 the osteology and myology of these j^uzzles must also be taken 

 into account — but we shall have made great strides when this 

 pteryological work has been thoroughly done. It is to be hoped 

 that those who use these volumes will endeavour to lake up this 

 muL'h neglected work. 



The juvenile or "nestling" plumage of the Passeres affords very 

 valuable data to tlie systematist. In the last edition of this 



