PROF. W. K. PARKER ON ZGITHOGNATHOUS BIRDS. 299 
this is the anterior extremity of the true “inferior turbinal” (7. ¢4). This turbinal is 
shown in the next section at its fullest development (fig. 6, seen from behind), a mere 
foot-shaped outgrowth from the little extended “aliseptal” region, this part being 
almost aborted by the huge nostril-covers (ale nasi). We shall see that in the Rook 
the “inferior turbinal” infolds itself two and a half times, in the Fowl twice, in the 
Rhea (“Ostrich Skull,” pl. 10. figs. 14 & 15) and in the Tinamou (ib. pl. 15. fig. 9, #0) 
three times, whilst in the “ Casuarine” (ib. pls. 10. & 12) this fold breaks up so as to 
be a veritable “ arbor vite” in section. In this section (fig. 6) the septum (s. 7) is thin- 
ning out towards the hinge; the alinasal wall is coiling inwards and thickening, still 
having its huge turbinal flap (a. tb); close behind this part the long submesial flap is 
tied strongly to the vomerine cartilage (fig. 8, lower view). The floor-flaps (a. f) 
are very large here; near their end their strongly bowed inner faces are very close 
together. 
The next section (fig. 7) is viewed from behind ; and the left antorbital plate or “ pars 
plana” (p. p) is cut away: it is very large, as is shown on the other side. Between 
the alar and median parts of the fast-hardening ethmoid (p. e) and the antorbital 
wall there is a large open space, admitting the ingress of both first and fifth nerves 
(1, n. 2). 
This ecto-ethmoidal cartilage (upper ethmoid and pars plana) appears on the surface 
above and laterally; hence the abortion of the lachrymal, as in the Passerine. 
There is nothing to be called “ upper turbinal” (w. t@) except the circular infolding of 
the aliethmoid (a/.¢) just in front of the antorbital wall; and the “ inferior turbinal”’ 
shows a greater curvature just in front of that wall. The ‘“ middle turbinal” is only 
represented by a somewhat ridgy condition of the great posterior plate, between the 
other two. Having studied these parts in the highest Amphibia (ana) and in the . 
Snake, Lizard, Crocodile, and Turtle, I am enabled to say that the “ 'Turnicomorphe,” 
although formed on the ornithic plan, yet have their nasal labyrinth very little in ad- 
vance of what is seen in those cold-blooded types, and considerably below that of the 
“saurognathous” Woodpeckers. The postoral region presents a peculiarity which can- 
not be passed over, although the plan of the present paper does not strictly include 
those parts. 
In my former Plates of these birds I figured in H. varius a large tympanic (“ Gallina- 
ceous Birds and Tinamous,” pl. 35. figs. 1 & 2), and in the other species (pl. 34. figs. 1 
& 2) a larger and a smaller bone; but in this invaluable skeleton, lent me by Mr. 
Salvin, I find s¢x (Pl. LIV. fig. 12, ty)! and the last but one of this chain is much the 
larger, and is folded upon itself like a viper’s tooth, as if to enclose some tube. I am 
not certain whether the “ siphonium,” which carries air into the lower jaw, is embraced 
by this bone or not; in my next instance it is, as I will soon show. 
Considered by itself, the Hemipode is a low type of the “ Carinate,” more reptilian 
in some respects than the “ Ratite” down below it. Butif it be looked at as a remnant 
282 
