THE NASAL BONES OF BIRDS. 127 
nasal process of the premaxilla, and the outer descends free to join 
the maxilla. In these birds there is. considerable variation in the 
manner in which the almost detached outer of the two nasal processes 
joins the body of the bone. In Numenius, Hematopus, and many 
of the Limicolz they proceed directly upwards and expand, becoming 
slightly fanned out where they join the rest of the bone by a straight 
transverse line. In Ibis and Grus they are of uniform size from end 
to end, whilst in the Auks, and to a less degree in the Gulls, at its 
_ origin the process is slightly curved, being directed outwards for a 
short distance, and after that straight downwards and forwards. 
In most schizorhinal birds, a transverse line joming the extreme 
posterior point of one external nasal aperture to the similar one of 
the opposite side is situated behind the posterior ends of the nasal 
processes of the premaxilla; but in some of the short-beaked broad- 
mouthed species of the class it is situated in front of them. Such is 
the case in Pterocles and Syrrhaptes ; and this peculiarity renders it at 
first sight uncertain whether they are schizorhinal at all; but as every 
intermediate condition may be found between the strictly schizorhinal 
skull of the Columbide proper, and the very similar but less strongly 
marked skull of Pterdcles, there is no real reason to doubt that the 
modification only depends on the great breadth of beak in the latter 
- bird. The curious development of the superficial nasal turbinal bone 
of Pterocles is also a Columbine character, as is also the great length 
of the inner of the two nasal processes, which, in a manner quite un- 
like that of the Galline, extends on each side for a long way forwards 
under the premaxillary nasal splint. 
Subjoined is a list, alphabetically arranged, of the genera in which 
I have observed the schizorhinal arrangement :— 
ScHIZORHINAL Birps. 
Alea. Grus. Rhinochetus. 
Anous. Hematopus. Rhynchops. 
Anthropoides. Ibis. Rissa. 
Arctica. Larus. Sarciophorus. 
Cataractes. Lestris. Scolopaz. 
Charadrius. Limosa. Sterna. 
Chionis. Machetes. Totanus. 
Dromas. Numenius. Tringa. 
Eurypyg. Parra. Turniz. 
Fratercula. Platalea. Uria. 
Gallinago. Pierocles. Vamellus. 
Glareola. Recurvirostra. 
And all the Columbidz proper. 
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