( 1-^^ ) 



the smaller size of the popliteal fossa. These distinctions are, however, extremely 

 sligiit. But the femora of these two species may at once be distinguished from 

 that of any of the smaller Corvidae by their greatly superior size, and the dei.'p 

 cnp-shapod cavity at the base of the external trochanter, for the origin of the 

 tleuor perforans digitorum profumhis only a very faint depression marking this 

 spot in the smaller Corvidae. 



The tibio-tarsus in Falneocorn.r is as long as in the Raven, herein affording 

 further proof that the fossil bird was relatively much longer in tlie leg and shorter 

 in the wing than in the Raven. Bnt tlie tibio-tarsus of Palaeocorax may readily 

 be distinguished by the smaller size and triangular shape of the entocnemial 

 process, and by the mnch greater development of the muscular ridge immediately 

 beneath and laterud of this process. The cctocnemhd crest is also smaller than in 

 the Raven, and the fibular crest is shorter. The tibial shaft is also more slender — 

 actually and not relatively, the shaft is of equal length in tlie two species. The 

 extensor bridge in the Raven is wider and more obliquely sloped than in 

 Palaeocorax. Finally, the external and internal trochleae of the distal extremity 

 of the shaft have an almost circular contoi.r in J'alacocoiax, while in the Raven 

 the contour is elliptical. 



The tarso-metatarsal shaft in Palaeocorax is actually longer, and is also more 

 slender than in the Raven. In the former it has a length of 7.5 mm., in the latter 

 of 71 mm., a difference which, having regard to the markedly superior size of the 

 Raven in other respects, is considerable. The bony bridge, above the tubercle, 

 for the insertion of the tibialis aiiticiis, under which passes the tendon for the 

 extensor longus (ligitorum, is wanting in Palaeocorax. Finally, the distal trochieac 

 are smaller, and the muscular ridges down the back of the shaft are less developed, 

 indicating a much less powerful foot than tliat of the Raven. 



SUMMARY. 



Only in its smaller size, and in the character of the palate, does the skeleton 

 of Palaeocorax differ in any material degree from that of Corax, and it is therefore 

 open to argument whether it was necessary to regard these remains as representing 

 a bird generically distinct from the Raveu of to-day; for the differences herein 

 described are those of degree rather than of kind, as may be gathered from the 

 facts which a survey of the skulls of other Corvidae have brought to light. 



Palaeocorax, though markedly smaller than the Raveu, was yet relatively 

 a longer-legged bird ; this much is obvious from the fact that the femur and tibio- 

 tarsus were as long as those of existing Ravens, while the tarso-metatarsus was 

 actually longer. The greater length of this limb, coujiled with the relatively 

 smaller wing, sliallower carina sterui and smaller pygostylc, show that Palaeocorax 

 was not a migratory bird, or addicted to long flights. The characters of the jialate 

 rather indicate specialisation than a primitive condition. 



That this bird was a Raven, and not a t'row, seems evident, since, though 

 decidedly smaller than tLie Raven, it was larger than any Crow. It seems, indeed, 

 to have occupied au exactly intermediate jiositiou between the two. 



