50 MR. W. P. PYCRAFT ON THE [May 2, 



of those on either side. In section the shaft is subcylindricah 

 Mc. I. is long, as in the Passeres. 



The pelvic' limbs of the Eiuyhemidfe and Cotingidfe can be 

 distinguished from the limbs of the syndactyle members of the 

 Ooraciiformes by the fact that, in the latter, the tarso -metatarsus 

 is either broad and flat, or deeply grooved anteriorly, and is more 

 or less triangular' in section. Fui'ther, the cnemial crests of the 

 tibio-tarsus are, in the Ooraciiformes having this type of feet, but 

 feebly developed. 



X. Summary. 



Regarded, by common consent, as the most lowly of the 

 Passeriformes, the Euiylpemidje are at the same time an extremely 

 specialised group ; much more so than has been hitherto recognised. 

 Such a condition might have been expected indeed, inasmuch as 

 this is a common feature among primitive groups. 



Nowhere is this specialisation more conspicuous than in the 

 skull. The basipterygoid processes have entirely disappeai-ed ; 

 the maxillo-palatines have been reduced from broad triangular 

 plates to rod-like splints ; and a singularly perfect fronto-nasal 

 hinge has been deA'eloped. In some genera, as in Corydon, the 

 beak has vastly increased in size, and has acquired a markedly 

 hooked shape, as well as a great increase in breadth. Nor is this 

 all. The vomer presents a number of gradations in the direction 

 of reduction and degeneracy ; and this is true also of the nasals, 

 whereby the anterior narial fossa — which, by the way, is only in 

 fact a narial fossa in so far as its extreme anterioi-end is concerned — 

 is enormously enlarged. The lachrymal has been reduced to a 

 mere vestige embedded, though still free, in the anterior face of 

 the antorbital plate as in Calyptomena, or it is wanting as in 

 Corydon. The palato-pterygoid ai-ticulation is also specialised ; 

 so too is the nature of the vomerine support, this having been 

 transferred from the pterygoids to that of the palatines. The 

 hemiptei-ygoid element appears to be wanting, but traces of this 

 may turn up in the nestlings of Calyjitomena. 



Evidence of yet further sj^ecialisation is obtained from a study of 

 the nestling skull. Besides the disappearance of the hemipterygoid 

 just referred to, the squamosal gives unquestionable proof in this 

 direction ; yet, at the same time, having preserved the essential 

 characters of its shajje, this element, more than any other bone 

 in the sk\dl, affords testimony of no uncertain kind as to the truly 

 Passerine character of the group. Roughly X-shaped, there can 

 nevertheless be no doubt, from the general contours of the bone, 

 that it has been derived fi-om a larger and more conical plate 

 resembling that which obtains in the Corvidse for example. 

 Further, as in all the Passeres, the long axis of this bone is 

 continued upwards and forwards beyond the parietal so as, in short, 

 to overlap the fi'ontal. So far as I liaA^e yet been able to ascertain, 

 such an extension does not obtain anywhere among the Coracii- 



