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ON THE SKELETON OF PALAE O COB AX MOEIORUM. 



By W. p. PYCRAFT, M.B.O.U., A.L.S., Etc. 



[Published hy permission of the Trustees of the British Museum.) 

 Plate II. 



nnHE existence of the bird whieli forms the subject of this paper was first brought 

 -*- to light by Dr. H. 0. Forbes, who discovered numerous wing and leg bones of 

 a crow-like bird in recent, or late Pleistocene beach deposits, in Chatham Island. 

 These he described {Nature, xlvi. p. 252) as the bones of a member of the genus 

 Comis, since they were precisely similar to those of living members of this genus. 

 Later, however, skulls came to hand, and from an examiiiatiou of these Dr. Forbes 

 became convinced that these remains mnst after all be regarded as of a bird repre- 

 senting a new genus, to which he gave the name Palaeocorax* This bird, on 

 the new evidence, he contended, was intermediate in character between the 

 completely aegithognathons Coracomorjjhae, as represented by Corvug, and the 

 compound aegithogoathism of forms such as Gymnorhina. 



It seems open to question whether, after all, this bird is entitled to rank as 

 generically distinct from the genus Corar, and it is certain that it has no genetic 

 connection with Gymnorhina. 



The following jjages will, it is hoped, confirm these contentions. 



The Skull. 



Though the skull of Palaeocorax moriorum agrees very closely with that of 

 the raven, Cortus corar, it differs therefrom, and from all other Corvidae, in one 

 or two noteworthy particulars. 



In regard to size, as the subjoined measurements show, it is inferior to the 

 Raven, bnt exceeds that of any other member of the ( 'orvidae. 



Length. Tostorbital Wi.ltli. 



Palaeocorax . . . .112 mm. . . .47 mm. 



Corax 115 mm. . . . 50 mm. 



Corvultur .... 105 mm. . . .48 mm. 

 In its cranial characters Palaeocorax differs from Corvus corax, as to the 

 occipital region chiefly in the greater distinctness of the cerebellar prominence, and 

 the relatively shorter distance between the rim of the foramen magnum and the 

 lambdoidal ridge. In the lateral aspect of the cranium the differences are slightly 

 more marked. In the first place the postorbital process is both actually, and 

 relatively, longer, turns slightly outwards and forwards, and has the ridge for the 

 itermotemporalis muscle more strongly developed, while the " temporal fossa " for 

 the temporalis muscle is less circular in outline. Though the difference in the 

 form and size of this process is not very great, it materially changes the form of 

 the orbit, since in the Raven this cavity has the form of a long antero-posteriorly 

 truncated oval, while in Palaeocorax it is circnlar. Further, while in Corvus corax 

 there are two deep depressions for the orhitomaxillaris muscle, in Palaeocorax the 

 superior border of the scar marking the origin of this muscle takes the form of a 

 'o"g .JS'gged line or ridge running outwards to the postorbital process. 



♦ Bull. Brit. 0)11. Club. 1892. p. xxi. i 



