1907.] 



TO THE OSTEOLOGY OF BIRDS. 



355 



development. Opening immediately above the squamosal and otic 

 articular surfaces for the quadrate, the latter leads upwards into a 

 chamber filled with cancellated tissue. 



Text-fig. 101. 



to. 



.fo.ojo. 



p o fo. 



Lateral aspects of the skulls of : — ■ 

 a. Gymnorliina organicum. \3. Laniaritis polio cephalus. C. Sayornis cineracea. 



d^n. = anterior nares ; a.o.p. = antorbital process ; I. = lachrymal ; pa. = palatine ; 

 p.o.p. = postorbital process ; pt. = pterygoid ; p.z.s. = processus zygomaticus 

 squamosi. 



The Postorbital Region presents one or two noteworthy 

 characters. The Pittidfe alone develop extensive, but shallow 

 temporal fossse, which are separated one from the other, in the 

 middle line, only by a median sagittal ridge. In the Tyrannidse 

 and in the Phytotomidse this fossa is, though narrower, relatively 

 deeper than in the Pittidfe ; but it is confined entirely to the 

 lateral aspect of the cranium, extending backwards, roughly, as 

 far as a point midway between the free edge of the tympanic 

 cavity and the centre of the lambdoidal ridge : the distance 

 varying in different genera. In the remaining Families dealt 



