OSTEOLOGY 



and in the hawks bearing a second and separate bone 



behind. These bones appear sometimes to have a definite 



relation to the cartilaginous ectethmoids. I do not refer so 



much to the fact that they sometimes entirely fuse with 



them (and with the skull wall) as to the varying size and 



relations of the two. In the kingfishers, for example, where 



the ectethmoids are small, the lacrymals are large, and have 



below an expanded plate which supplies the place of the 



feeble ectethmoid. When the lacrymal does not reach the 



orbital margin, as in Corvus, the 



ectethmoid does, and, as it were, takes 



its place. In many birds belonging 



to quite different orders there is a 



small bone connecting the lower end 



of the lacrymal, or of the ectethmoid, 



with either the palatine or the jugal 



bar ; this bone has been termed ' os 



crochu,' os uncinatum, os lacrymo- 



palatinum, and will be described in 



detail in those birds where it is to 



be found. 1 It may be that the os 



uncinatum should have been de- 



scribed as one of cartilaginous bones 



of the cranium. In some birds (tina- FIG. 7G. HYOH> OF Latha- 



mous, Menura, Psophia, and A rbori- discolor 



Cola) there is a Set Of SUpraOrbital &, basihyal ; M, hypnbrancliial : .*, 

 , . . , i -j. i ceratobranchial ; , uroliyal ; c, 



DOIieS margining the OrbltS abOVe. entoglossum ; }>, parahyal ; c, cou- 



The base of the brain case is protected 



by a large basitemporal, which has sometimes (e.g. Apteryx) 

 a long rostrum in front. The maxillae are sometimes sepa- 

 rate from each other, and at times united across the middle 

 line by more or less extensive ossifications, of which a pro- 

 minent one, and with the appearance of a separate bone, 

 is the maxillo-palatine. The premaxillaries in front of these 

 send back a long process extending as far as the nasals. 



'2. To this category, perhaps, belong the squamosal, 



1 See under Cariauta, Tubinares, Steganopodes, Musophagi, where cross 

 references will be found. 



