216 MR. W. K. PARKER ON THE OSTEOLOGY 
Ostriches, seeing that in them it is not more than partially differentiated from the orbit ; 
for in them the lachrymal does not reach to the zygoma, nor the posterior crus of the nasal 
to the ascending spur of the prevomer. In many birds, especially Plovers and Fowls, 
the nasal processes of the premaxillaries are very unapt to ,anchylose with each other 
(Pl. XXXVI. fig. 7, & Pl. XX XVII. fig. 3, pw.): in the ‘‘ Struthionide” this is the first 
thing to take place (Pl. XLII. fig. 2, px.) ; and in Struthio camelus I have found that in an 
embryo with the head only an inch and a half long these processes had coalesced, whilst 
the beak-part of the bone had not its two sides fused, and the cartilaginous scaffolding 
(the prevomerine, evanescent rostrum) still showed itself between the two bones on the 
upper aspect. The Tinamou (Pl. XL. fig. 2) answers to the Ostriches in this respect ; 
for the nasal processes of the premaxillaries are quite fused, and are, relatively, broad 
as well as long: in the Ocydromus there is a considerable approach to the Ostriches in 
this respect. In the Tinamou (Pl. XL.) the beak-part of the premaxillary is only 43 
lines long, whilst the nasal part is 13 lines ; but it is altogether struthious, with its 
well-defined lateral groove on each side, and its large vascular puncta so close and 
with such small interspaces as to convert this part of the bone into something like the 
stony tissue of a madrepore (Pls, XL. & XLII.). The palatine processes of the pre- 
maxillaries reach backwards more than 13 lines from the tip of the bone; they are 
separated from the ‘‘ dentary”’ margins by the prevomers, and are, like all the sub- 
nasal portion of the bone, extremely thin, fibrous, and translucent (Pl. XL. fig. 1). The 
dentary portion of the bone, after it has become distinct by the inwedging of the pre- 
vomer, is a very delicate rod (figs. 2 & 3), and ends at the foot of the inferior crus of 
the nasal: in the Rhea this process does not go so far backwards. I have no maxillary 
bone to describe in this bird, nor should have in by far the greater number of birds ; at 
present I have only found it in the Emu a week before hatching ; in the fledgeling 
Swift (Cypselus apus) it seems to exist as an upper mouth-angle scale of bone; and it 
is certainly present in Nycticorax ardeola and in Herodias garzetta, even in old birds, 
and in a few others. 
It is, however, when present, a very minute piece, outside the other face-bones, and 
close behind the dentary angle of the premaxillz. But the bones (Pl. XLII. figs. 1, 2, 
& 4, pv.) which have hitherto been mistaken for the superior maxillaries in birds, and 
which have long been a puzzle to both Professor Huxley and myself, are, I am tho- 
roughly satisfied, nothing more than the homologues of the bones which, in the Python, 
were called by Cuvier ‘‘ cornets inférieurs.”” They exist in the Amphibians, Lacertians, 
and Ophidians, but not in the Crocodiles and Chelonians, nor in the Mammalia. If 
they were present in those animals, we should see them filling up the ‘‘ anterior palatine 
foramina,” underlying the outspread anterior part of the septum nasi, and articulating 
with the outer edge of the anterior part of the vomer. In this place I can only assert 
the truth ; it must be proved fully in another kind of paper. 1t was necessary, however, 
to make a clearance of this particular stumbling-block before proceeding with the palate 
