SHUFELDT. | OSTEOLOGY OF THE CATHARTIDA. 745 
vulture-wards. In this bird the superciliary process has shrunk up in 
size, articulates principally with the margin of the nasal, while the body 
of the bone below engages the entire border of the ethmoid, all the 
natural traces being evident. The roof of the orbit is formed by the 
frontal. A very decided change takes place among the Cathartide ; 
here complete anchylosis with the surrounding bones has taken place, 
obliterating all traces of original individuality on the part of the lacry- 
mal. By its aid the great width is attained across the fronto-maxillary 
articulation. (Pl. XXIV, fig. 127.) Its body below knits with the 
ethmoidal wing, and is produced downwards, backwards, and outwards 
so as to almost touch the infraorbital bar, as a club-like process in Sarcor- 
hamphus gryphus and P. californianus. Its outer side shows the groove 
for the lacrymal duct. By the assistance of the lateral extensions of 
the ethmoid, these bones make a very substantial partition between the 
orbital cavities and the rhinal chamber; above and between the two 
there is an opening for the passage of the nasal nerve and vessels. 
It is difficult to say, from an examination of the skulls of the adult 
birds, whether the vomer exists in them as a separate ossification or not; 
we are of the opinion, however, that it does not; at any rate, there is 
no such bone present as we find among many of the Ducks and Geese 
(it must be remembered, however, in this connection that this delicate 
little vone is often lost in the maceration and preparation of avian 
crania). 
The ethmoid (the mesethmoid of Parker) meets the vault of the rhinal 
space above in a spreading abutment; from this point it takes a direction 
Catharista atrata. 
downwards and backwards in the mesial plane, to become consolidated 
with the extremity of the basi-presphenoid, below. Behind, by extension 
of its median osseous plate, it assists to complete the orbital septum, 
while laterally it develops on either side alar productions that amalga- 
mate with the lacrymals, as pointed out above. On its anterior face we 
have presented us a sharpened edge, extending up and down the bone 
in the mesial plane. The lateral wings in C. aura are removed far to the 
back, and they have from their lower boundaries horizontal plates de- 
veloped that reach forward beyond the basi-prespbenoidal tip, to the 
