802 
ME. W. K. PAEKER ON THE STRUCTURE AND 
In the side view* of the skull of an old male (Plate LXXXVII. tig. 1) we see how 
largely the face has gained upon the skull as compared with what had obtained in the 
ripe chick (Plate LXXXIV". figs. 6-9), where the face had the feebleness seen in the 
Sand-grouse ( Syrrhaptes ). 
A zygomatic process has grown downwards from the squamosal (Plate LXXXVII. 
fig. 4, sq.), and this has formed a bridge over the lower part of the temporal fossa by coales- 
cence with the postfrontal (p.f.). The fenestrae in the posterior orbital wall are all 
filled up, and the olfactory opening (1) is merely large enough for the nerve, whereas it 
once lay in a sheet of membrane. 
In Plate LXXXVII. fig. 4 a trace of the interorbital space ( i.o.s .) still exists ; but in 
another specimen (fig. 8) the periosteal layers of bone have completely obliterated it ; 
in the same figure which shows the inside of the cranial cavity and the left side of the 
orbital septum, it is seen that the rostrum ( r.b.s .) has completely coalesced with the base 
of the perpendicular ethmoid (p.e.), and that the upper part of the ethmoid ( etli .) has 
stopped its ossification at the cranio-facial isthmus. The nasal labyrinth, which is not 
displayed in these figures, is but little altered since the first winter (Plate LXXXVI.) ; 
but four small endosteal patches have appeared (Plate LXXXVII. fig. 10) in front of 
the ethmoid ( etli .). One of these is in the isthmus ; another, close in front of it, is 
formed in the postero-superior margin of the septum nasi ( s.n .) ; and on each side of these 
there is one formed in that thick bridge of cartilage which protects the upper branch 
of the nasal nerve (Plate LXXXVI. fig. 14, n.n.). In the late, arrested condition of the 
nasal ossicles, the Fowl differs much from a large number of Birds, especially the aerial 
Desmognathge ; and many also of the Schizognathse are less Beptilian in this respect than 
the Fowlf. The nasal bones (figs. 4 & 6, n.) have coalesced posteriorly with the frontals 
( f .); but the latter are wedge-like, and divergent in front, and thus expose the upper 
surface of the ethmoid ( eth .) : this is a Struthious character ; originally, however, it 
answers to the skull of the Osseous Fish ; it is occasionally seen in the Lizards, for instance 
the Iguana. The nasal processes of the premaxillaries (npx.) have neither coalesced with 
each other, nor with the surrounding parts; the maxillae (mx.\ the jugals (j.), the 
quadrato-jugals (q.j.), and the lacrymals (l.) keep their distinctness to old age. 
On the lower surface (Plate LXXXVII. fig. 5) the palatines (pa.) maintain their sepa- 
rateness from the palatine plates of the premaxillaries (p.), and also from those of the 
maxillaries (mx.). The small vomer (v.) also is merely attached to its surroundings by 
bands of fibrous tissue. The pterygoids ( p.g .) are attached to the palatines by a rough 
sort of hinge, and to the quadrate (behind) by a shallow cup, which receives the pterygoid 
facet of the quadrate. This latter hone (q.) acquires a strong trochanter in front of its 
* These figures of the skull of old Fowls are from preparations made in the usual way, namely, by destruction 
of the soft parts ; so that the nasal labyrinth and septum are not shown : these figures are good for comparison 
with those given of adults of related types in my paper on the Gallinse (Zool. Trans, vol. v. pis. 34-40). 
t These terms are taken from Professor Huxley's paper “ On the Classification of Birds,” Proc. Zool. Soc. 
1867, pp. 415-472. 
