56 



ADDITIONS TO THE LIST OF FOSSIL BIRDS, 



position as the radius is in the antebrachium, will be termed the 

 radial limb, the larger element for the like reason being styled the 

 ulnar limb. 



Noting, first, the absence of the bony bridge which, rising from 

 the dorso-radial edge of the ulnar limb, spans the interval between 

 it and the radial limb, and forms a characteristic feature of the part 

 in the perching birds, we observe in the form, extent, and direction 

 of the surfaces of articulation with the carpals, a guide to the 

 discrimination of this fragment of the bird-skeleton. It may be 

 said of the distal moiety of the articulation that it presents in very 

 many birds two elevated parallel and continuous ridges with an 

 intervening sulcus — the ulnar ridge the shorter ; in perhaps the 

 majority of birds, however, this ridge is more or less emarginate 

 proximad of its termination. The termination may itself be entirely 

 absorbed by the emargination, the ridge then appearing truncate. 

 In the Megapodidae alone of the Australian birds examined, this 

 ridge is continuous, but though distinct, it is feeble, almost linear, 

 and trends obliquely towards the radial ridge. The root of the 

 r adial limb, which in most birds is broad and depressed, in the 

 Megapodidse is narrow and convex — between it and the ulnar is a 

 groove running from the furcation of the two limbs proximad to the 

 ulnar edge of the articular sulcus. Such are the features which — 

 being present in the fossil, and occurring likewise in the Megapodida?, 

 and simultaneously in none other within the writer's scope of 

 observation — lead him to refer this bone to the mound-building 

 family. 



It remains to ascertain the genus. In this regard mere 

 superiority of size cannot be taken into account — antiquity even to 

 the extent of a geological period can only be allowed a casting vote. 

 But apart from these, the bone bears evidence adverse to its identi- 

 fication with either of the existing genera Talegallus and Mega- 

 podius — it combines characters of both with features peculiar to 

 itself ; with the bone in Leipoa the writer has no present oppor- 

 tunity of comparing it, his proposal of a new generic term for it is 

 therefore amenable to a contingency which renderi it little mor e 

 than provisional. 



