342 PROF. W. K. PARKER ON ZGITHOGNATHOUS BIRDS. 
cartilage (fig. 8, #7’, tr"). In front, the septal bone grows round the end and returns along 
the trabecular base, hookwise, up to the end of the expanded or alar portion (fig. 8, s. 2). 
The ale nasi and their various outgrowths and processes are such as, being well mas- 
tered, will explain the peculiarities of a coracomorphous nasal labyrinth, as compared 
with that of the Fowl and Hemipod. Yet these parts, in the Bell-bird, are curiously 
intermediate between those of the Hemipod and the Crow; and only by comparing all 
these together shall we see their real meaning, or make out a harmony between them. 
If the parts in the Fowl (Phil. Trans. 1869, pl. 86) be compared with what I have 
described in the Rook (PI. LV. figs. 1-3), it will be seen that the alinasal turbinal is 
given off from the roof’ in the Fowl, and from the wall in the Crow. In the Fowl, the 
alinasal wall is largely inturned; in the Rook, only at the end. In the Fowl, the wall 
having become the floor, coalesces behind with sides and base of the septum (tom. cit. 
fig. 3); in the Rook, this inturned part is continuous with, and ossified by, the com- 
pound vomer. In the Rook, the internasal part of the trabecule (PI. LV. fig. 2) is 
largely alate ; in the Fowl (tom. cit. figs. 1-4), the trabecule only caused the thickening 
to the base of the septum. But the most profitable comparison is to be made between 
the Crow and the Hemipod in these respects; and only by such a comparison shall we 
be able to see the meaning of these parts in the Bell-bird. 
There is evidently, amongst birds, a primary difference in the manner in which the 
primary nasal slit (see “ Fowl’s Skull,” pl. 81. fig. 1) becomes enclothed with cartilage, 
and drawn out into long, broken-up, labyrinthic passages. 
In the Crow and Warbler (Pl. LV. figs. 1 & 13, re. ¢) the alinasal scale of cartilage 
is, as it were, tucked in at its fore end, a broad flap on each side passing backwards and 
inwards to meet, and afterwards coalesce with, its fellow beneath the septum nasi. This 
T have worked out in the embryo of the Gorse-Linnet, and shall describe elsewhere ; 
these retral parts are in reality the ‘‘ cornua trabecule.” 
In the figures given of these parts in the young Rook and Redstart, these recurrent 
flaps have united at the mid line into a triangular tongue of cartilage (re.¢); but in a 
form to be given in my next part, namely one of the “ Vireonide” (Vireosylvia oli- 
vacea), the part is twice the size of what is here shown, and nearly the hinder half 
is ununited, so that it is a large forked flap, the “tines” looking backwards: this is a 
step towards what I shall describe in the Bell-bird. Now it is evident that in the Rook 
(Pl. LV. fig. 1) the air passes in between the recurrent alinasal lamine (rc. ¢) and the 
outer alinasal wall, with its ingrowing turbinal (a/.n, a.tb), the turbinal being lateral 
in its origin, and not superior as in the Fowl (doc. cit.) and the Hemipod (Pl. LIV. figs. 
3 & 4, a.tb); it arises, in the Rook, from the wa// behind the external nostril, and not, 
as in the Fowl and Hemipod, from the roof in front of it. Here also note another 
important difference—namely, that instead of the recurrent flap being an ingrowth 
backwards of the forefront of the alinasal roof, in the Hemipod it is given off from the 
wall (Pl. LIV. figs. 1, 3-6, n.w, n.f). So there is an exact reversal as to the origin of 
