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 

 (PI. XXXVI. fig. 7, & PI. XXXVII. fig. 3, px.) : in the " Struthionid^" this is the first 

 thing to take place (PI. 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 (PI. 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 Ocydrovius there is a considerable approach to the Ostriches in 

 this respect. In the Tinamou (PI. XL.) the beak-part of the premaxillary is only 4^ 

 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 (Pis. 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 (PI. 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 fledgehng 

 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 premaxillae. But the bones (PI. 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 inferieurs." 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. It was necessary, however, 

 to make a clearance of this particular stumbling-block before proceeding with the palate 



