OSTEOLOGY OF BIRDS 



21 



rhinencephalic fossa, we find that this concavity is also spacious, 

 lodging as it does the encephalic lobe that" presides over the sense of 

 smell. The orifice of exit for the olfactory nerves is double in 

 Cat h arista u r u b u , and some others of the Cathartidae 

 which is an exception to the general rule in Aves. Sir Richard 

 Owen found the same state of affairs in a vulture that he dissected, 

 and he said:" In the vulture the olfactory nerve is single on each 

 side, and continued from an olfactory ganglion or ' rhinencephalon ' 

 along the upper part of the interorbital space to be distributed upon 

 an upper and middle turbinal, the latter being the largest." [Anat. 

 Vert. 2:123] 



Along the roof of the cranial cavity, in the median line, the 

 " longitudinal crest " is seen to pass. This may become grooved as 

 it approaches its anterior termination, or for its anterior half, which 

 indeed is the case in the majority of these birds; the groove dilating, 

 and the whole merging into the general surface immediately before 

 arriving at the conical rhinencephalic recess just referred to above. 



Passing to the hynoid arches of Cathartes a. septen- 

 trional i s , we find that they practically agree with what we 

 find in the South American condor (Sarcorhamphus) . As in other 

 vultures the glossohyal remains in cartilage throughout life, and the 

 ceratohyals, as two, slightly curved, elliptical osseous plates im- 

 bedded in it at its base, articulate by the margins of the.ir posterior 

 arcs with the facets on the anterior aspect of the first basibranchial : 

 they are also tangent to each other at their middle points in the 

 median line. The first basibranchial is included in the great fleshy 

 base of the tongue in these birds, and is characterized by an osseous 

 keel along its nether aspect, while it is somewhat expanded laterally. 

 The second basibranchial is a slender spine, coossified with the first 

 and tipped off with cartilage behind. The thyrohyals and the ele- 

 ments that compose them are simple, being subcylindrical, some- 

 what curved rods of bone, the posterior pieces being finished off 

 with cartilage. 



I have not especially examined the intrinsic ossifications of the 

 ears in our vultures, and the only example of the sclerotal plates 

 that I have is a set from the eyes of a specimen of Cathartes 

 a. septentrionalis. In this vulture they number 15 in each 

 eye, are very abroad, overlapping each other by about one fifth of 

 their extent ; their corneal margins are turned outward, while their 

 sclerotal ones are reflected in the opposite direction. I have but 

 little doubt that when opportunity for examination offers, this 



