368 MR. W. p. PYCRAFT CONTRIBUTIONS [Apr. 9, 



even there it is fairly well developed, except in Pityriasis and 

 Euryceros^ which have a mai-kedly shallow keel. 



The posterior notches, though difiering slightly among different 

 genera, in the matter of length, do not afford any matter for 

 comment excejjt in the Paradiseida?, whei-e, by the expansion of 

 the free end of the posterior lateral process, the notch becomes 

 converted into a foramen. Whether, however, this character 

 obtains throughout the Paradiseida^ remains to be seen. 



The Goracoid shaft is typically passerine, being long and slender, 

 and having a broad flange extending along the outei- border of 

 the shaft from the base forwards nearly as far as the middle ; 

 while the acrocoracoid is long, turns forwards and inwards, and 

 sends backwards a hook-shaped process affording additional attach- 

 ment for the furcula. The procoracoid is obsolete or absent, 

 except in the Tyrannidfe and Phytotomida^, where it forms a long, 

 band-like spur affording a shelf for the articulation of the 

 scapula. 



The scapula affords no matter for special comment except in 

 so far as the acromion is concerned. In the Tyrannidfe and 

 Phytotomidfe this process is not so well developed as in the higher 

 forms herewith associated, inasmuch as it does not send down, 

 into the foramen triosseum, between the clavicle and the coracoid, 

 a spur for the support of the free end of the furcula. Instead the 

 postei'ior border of the pedate exjDansion of the free end of the 

 furcula rides in a trough hollowed out of the anterior face of 

 the acromion. In the remaining forms here described this method 

 of articulation also obtains, but the inner wall of the trough is 

 continued downwards to form the spur to which allusion has 

 just been made. 



lYie furcula presents a remai'kably uniform charactei- through- 

 out this series, varying, to any appreciable extent, only in the 

 foi'm of the expanded free end of each limb. In all, the hypo- 

 cleideum is more or less oblong and directed upwards, so as to 

 present a nearly vertical face towards the anterior border of the 

 carina sterni. In the Tyrannidfe and Hirundinidae each limb 

 terminates in a roughly spatulate free end the postero-superior 

 angle of which is received into a groove in the acromion of the 

 scapula. The middle region of the outer surface of this plate 

 is applied to the acrocoracoid, thus enclosing the foramen tri- 

 osseum. By way of contrast a compaiison should be made with 

 say the furcula of Gymnorhina. Here the free end is roughly 

 T-shaped, while it articulates with the anterior face of the acro- 

 mion rather than with its end, a relationship? which, it may be 

 noted, may be seen in its incipient stages in the Tracheophonae. 



The foramen triosseum, then, in the Tyrannida? is bounded, 

 without by the acrocoracoid, and on the inside by the expanded 

 free end of the furcula and the aci'omion of the scapula — these 

 two elements articulating by means of two opposed surfaces set 

 ti-ansversely to the long axis of the scapula. The higher Passeres 

 differ only in that the articulation between scapula and furcula 



