AND DEVELOPMENT OF THE BIRD'S SKULL. 137 



is burrowed by the nasal nerve ; and above and in front of this burrowing there is a 

 transverse septal knob, where the inturned alinasal fold joins on to the septum. On 

 each side the large, spongy, pneumatic maxillo-palatines (mxp) flank the septum, and 

 have the fore end of the knife-shaped vomer (v) between them. The palatines (pa), tbe 

 mesopterygoids (mspg), and the pterygoids (pg) conform very closely to those of the 

 Sparrow- Hawk. 



In the Harrier (Circus cyaneus) and in the Brahmany Kite (Haliastur Indus) I find 

 a separate, thin, "median septo-maxillary," attached, vertically, to the upper edge of 

 the vomer. It is very possible that this state of things may be merely the appearance 

 of a second vomer ; I am not certain on this point ; parts primarily symmetrical do at 

 times become azygous or median by the overgrowth of one and the arrest of the other, 

 the stronger bone gaining the mid line, and dragging the feebler bone after it. 



These feebler types have, as a rule, a flat superorbital on the free end of the long 

 superorbital process of the lacrymal. In the Falcon the ossification is continuous 

 along their frowning brow. 



The reader is referred to Prof. Huxley's " Classification of Birds " (Proc. Zool. Soc. 

 1867, p. 442, fig. 24) for the palatal view of the Secretary's skull : that figure is defi- 

 cient ; it should show a small knife-shaped vomer, like that of a Powl. The whole skull 

 of that bird comes very near to that of the Brahmany Kite (Haliastur indus) and to 

 that of the Egyptian Kite (Elanus cceruleus). Its general skeleton is hugely modified 

 on account of its stilted Crane-like stature ; legs of any indifferency would have asked 

 for none of those specializations of shoulder and hip-girdle which we see in that type. 



On the Palatine Bones in Eagles and Vultures. 



I shall merely note a few things to be seen in these large groups of the gigantic 

 Baptores. 



In the Bateleur Eagle (Helotarsus ecaudatus) there is a small median palatine (Plate 

 XXV. fig. 9, mspg) between the ethmo-palatine laminae. 



In Neophron percnopterus I find a delicate knife-shaped vomer (Plate XXV. figs. 14, 

 15, v), the right, fork of which is evidently aborted by a small mesopterygoid (mspg) ; 

 and besides this, on the same side, there is another granule of bone, belonging to the 

 same region (fig. 16, mspg). At the end of vomer, thinned out, however, in front, there 

 is a small medio-septomaxillary (msmx). 



In Gyps fulvus there is an unlooked-for amount of differentiation of the palatine arch ; 

 for even in old birds a sharp sutural line runs obliquely two thirds across, almost sepa- 

 rating the transpalatine (Plate XXV. figs. 17, 18, tpa) from the rest of the bar. Here also 

 I find a strong wedge-shaped mesopterygoid (mspg) permanently distinct. 



Eor the skull of Cathartes aura the reader is referred to Prof. Huxley's paper (op. 

 cit. p. 440, fig. 22); it is an instance of "indirect desmognathism," the maxillo-pala- 

 tines not being developed more mesiad than in Plovers and Pigeons ; but the bond 

 being formed of an ossified tract of the septum nasi and inturned alinasal fold, this 

 forms a bony bridge similar to that seen in the Cariama ; but there it is the anterior 



