306 MR. W. r. rYCKAFX ox THE [-^pi- 1^^> 



isohiuiu. In many form;?, as iu smuo species of Falco, llerpe- 

 tothcres, I^Ianoides, £laiii>!>', Splloruis, Accipiter, the iiie'liau 

 portion of the pubis has dis;ippeared, the proximal portion fusing 

 Avith the isehiuu\. immediately behind the obtui~ator foi-amen, 

 whilst the distal (hinder) ends are attached to the posterior 

 Ixn-der of the ischium. Thus sevei-al grades in the degeneration 

 of this Ixnie are presented. Sometimes the two portions are 

 connecteil by a vei'v slender thread of bone. 



The iliac recess in K>t'rpe)itarii(S is spicious. and extends back- 

 wards into a ].xx^ket-shaped cavity, a^ in K^iils. This pocket is 

 wanting, or but feebly developed, in the other Falconifoi-mes, 

 except Pandion, but it is interesting to note that it is univeis;iily 

 present in the Striges. 



vii. The Pectoral Limb. 



Kot only is there little vai'iation in the form of the wing 

 between the different membei'S which ai-e included in the present 

 gfoup; but there is also a strong resemblance between the wing 

 of the Falconiformes and that of the Grucs on the one hand, and 

 the Storks oti the other: the resemblance to the Crues being 

 especially mai-ked. 



The following characters displayed by the hitmenf^ will help in 

 distinguishing between the wings of these thi-ee groups : — In the 

 Falconifoi-mes and Grues the scar marking the insei-tion of the 

 pectoiul muscle I'uns along the free boi-dei' of the tiiangulai- pectoial 

 crest from the tiiherculiim extermis till it reaches the summit of the 

 ti'iangle, whei-e it expands into a In-oad elliptical space occupying 

 the lower limb, and, in the Cathai'tiv, extending on to the shaft. 

 In the Ciconi;^ the distal extremity of this scar takes the foi-m of 

 a strongly-iaised. linguifoi'm plate which lies partly on the shaft of 

 the humei-us and partly at the base of the distal limb of the crest ; 

 instead of occupying neai-ly the whole ci-est. The hnmei-iis of the 

 Falconiformes may be distinguished from that of the Grues in 

 that, in the foi-mer, the subtrochanteiic fossa is lai'ger, the distal 

 extremity of the hitmerus is much wider, and its ulnai' tuberosity 

 much moi'e pi-ominent. 



The coraco-humeral groove appears to be mai-kedly ileveloped 

 only in Pandion. In other forms it is either imlicated only by a 

 very shallow groove, or by two depressions. The head of the 

 humerus in the Falconiformes is more compi'essed fi-om palmar to 

 dorsal sui'faee than in the Grues. The supra-conilylar dejn-ession 

 for the brachialis inferior varies in its development. In Pandioii, 

 for example, it is deep with gently sloping siiles ; in (Tj/pagits the 

 floor is flat and oval and is bordei-ed by a Avell-defined i-im impei-f ect 

 distitlly: in Falco and Accijuter again it is barely traceable; 

 in Serpentarius it is an oval depression placed i-athei- high up in 

 the shaft. A small tubercle only, i-epresents the ectepicondylar 

 process. The form of the pectoral crest varies. In Serpentco-ins, 

 PaiidioH; and Falcons it is sliai-ply tiiangulai', and in Pandion 



