46 Transactions of the 



highly specialized ; heing indeed, as to skeletal mechanism, the most 

 wonderfully endowed of all the Birds. Not only their whole body, 

 fitly joined and compacted together, but every several limb and every 

 hinge and joint is in itself a paragon of form, strength, and elegant 

 lightness. Still, my proper business is not with these final results, 

 but with those still-life vegetative processes by which these special 

 ends are brought to consummation. 



Looking at the side view of the skull (Plate V., Fig. 1), it is at 

 once seen how the fierce face of an aquiline bird " is modelled on a 

 skull," which differs from that of other birds only by the gentlest 

 modifications. Indeed, it were not an impossible task to make a dia- 

 gramatic figure of a Carinate bird's skull that should serve as a 

 general illustration for the whole of the feathered nations. Amongst 

 these Plunderers there is one bird, the South American Cariama, 

 which combines the characters, otherwise seen separately, of Owl 

 and Vulture, Eagle, Falcon, Hawk, and Secretary Bird, whilst it is 

 also unmistakably related to the Cranes and Fowls. 



Looking at the skull from beneath (Plate V., Fig. 2), we see 

 that already the process of ankylosis has greatly effaced the occi- 

 pital sutures, and the basi-sphenoidal and basi-temporal tracts have 

 melted into each other. The occipital condyle (o. c.) is transversely 

 largest, having more of the Lacertian form than in the Singing-birds. 

 The " ex-occipital tympanic wings " (t. eo.) are still edged with car- 

 tilage. The parasphenoid has formed large trumpet-shaped recesses 

 to the tympanic cavity {a. t. r.), and on the lips of these tubes, 

 behind, I have seen, in older specimens, as many as three " tym- 

 panies " on one side. In still older specimens these have coalesced 

 together, and with the trumpet lip. Good, stout basi-pterygoids 

 appear on the base of the " rostrum " (b. pg.), and these, although 

 pointed, and scarcely functional, are permanent. The " parasphenoidal 

 rostrum " (Figs. 1 and 2, pa. s.) is thick behind, and comes upwards 

 to a fine point in front, behind the great " cranio-facial notch," 

 which is slowly pushed upwards in the adult, the cartilage becoming 

 absorbed between the ethmoidal and septal ossifications. The former 

 of these (Plate V., Fig. 1, p. e.) is now a huge plate of bone, 

 running forwards to the "notch" (hidden in the figure ty p- p.) 

 and backwards towards the " pras-sphenoid " above and the basi- 

 sphenoid below (p. s., b. s.) ; its posterior crescentic margin em- 

 braces the front of the pear-shaped " interorbital fenestra" (t. o.f). 

 The basi-sphenoid (b. s.) is ossified, and is continuous behind with 

 the huge grafting wings of the " parasphenoid," and has coalesced 

 by its lower surface with the basi-temporals (b. t.). Within the 

 skull it is being fixed into the margins of the "periotic" masses 

 and basi-occipital (b. o.). Seen from behind (Plate VI., Fig. 4), the 

 large, once double, supra-occipital (s. o.) is still partly traceable as 

 distinct from the ex-occipitals (e. o.), and in this view the " epiotics " 



