I4 THE AMERICAN NATURALIST. [Vor. XXXV. 
good-sized ramal vacuity is present in either ramus, and the 
straight and blunt angular processes are considerably produced. 
Kitchen Parker has said the “differences between the skull 
of Pterocles arenarius and Syrrhaptes paradoxus are not great, 
but are important. The head and face of the former are 
altogether stronger, more gallinaceous and less pigeon-like, 
than in the latter. The skull base has, in the Pterocles, that 
peculiar breadth which arises from the struthiousness of its 
structure. The upper frontal region is broader between the 
eyes, and the ale of the ethmoid swell up to a greater extent 
between the crura of the nasal The postorbital and squa- 
mosal processes are much stronger, and make a thicker bridge 
over the temporal fossa. The crossing of the posterior and 
horizontal semicircular canals project in the same hemispherical 
manner as in Syrrhaptes, and the tympanic ala of the lateral 
occipital is equally arrested.” 
“The molar arch is stronger, and the central interorbital 
space is filled up;! so also are the orbito-frontal fontanelles ; 
the common optic foramen is more closely and neatly circum- 
scribed. There is still an oval slit, opening into both orbits, 
between the ethmoid bar and the lower edge of the frontals at 
their coalescence. Theantorbital lachrymal mass is equally large, 
and the septum nasi as well developed and as completely ossified.? 
‘The bones of the face generally are quite as strong as in 
ordinary pigeons, and therefore a degree beyond what is seen 
in Syrrhaptes. The double head of the os quadratum agrees 
with the same structure in Syrrhaptes, and there is nothing 
special to remark upon in the bones of the palatine region. 
The lower jaw is altogether stronger and deeper, its bend is 
more marked and further back, than in that of Syrrhaptes ; 
the membranous space is of about the same size, as are also 
.the angular processes." 3 There is an excellent account of the 
skull of Syrrhaptes, including the bones of the tongue, etc., in 
the work of Professor Parker just quoted. It is interesting to 
! Not so in all specimens. — R. W. S. 
? The septum narium does not always EROS ossify in all individuals of 
this group ; it may, however, do so in the skulls o: old specimens. — R. W. S. 
3 On the Osteology of Gallinaceous Birds and Garni (p. 204). 
