178 MR. W. P. PYCRAFT ON THE MORPHOLOGY AND 
in the Dinornithide as the vertical plate dividing the pre-sphenoid fosse. There is a 
well-marked supra-orbital fenestra. 
The Dinornithide are apparently peculiar in the development of a pair of well- 
developed triangular processes, forming a horizontal plate projecting from the ventral 
border of the mesethmoid, and extending outwards to the level of the lachrymal. 
In Apteryx the ossified ectoethmoidal plates form two oblong, much inflated bulle 
on either side of the head, nearly filling up the very small orbit, the horizontal plates 
of the mesethmoid sweeping outwards, downwards, and inwards, the ventral edge 
fusing with the mesethmoid immediately above the parasphenoidal rostrum. Forwards, 
the part corresponding to the antorbital plate affords support to the lachrymal, as in 
Dromeus. 
As the late Prof. T. J. Parker has pointed out [71], ‘‘One of the most striking 
characteristics of the skull of Apteryx is the extreme complexity of the turbinals. When 
the mesethmoid is removed there are seen in the olfactory chamber proper four well- 
marked obliquely vertical folds, while a fifth is continued into the narrow or respiratory 
portion of the nasal cavity. The three hindmost of these folds are perfectly distinct 
one from another, and I propose to call them, respectively, the anterior, middle, and 
posterior turbinals. The fourth and fifth folds are intimately connected with the 
anterior turbinal: I call the uppermost of the two, which forms part of the olfactory 
region, the anterior accessory turbinal, and that which extends forwards, and has no 
olfactory function, the ventral accessory turbinal. 
«All the turbinals, with the exception of the ventral accessory, are covered by 
Schneiderian membrane, and are therefore analogous to the ethmo-turbinals of a mammal. 
The ventral accessory turbinal is covered with ordinary mucous membrane, and belongs 
to the merely respiratory portion of the nasal chamber ; it may be compared with the 
maxillo-turbinals of mammals. 
“On each side of the ventral edge of the mesethmoid, in the vomerine region, .... . 
is a slender rod of cartilage, imbedded in connective tissue, and lying parallel to, and 
either immediately dorsad or slightly laterad of the dorsal edge of the trough-like 
yomer ..... it can be readily prepared in a well-macerated skull by carefully 
removing the vomer. It is obviously the vestigial cartilage of Jacobson’s organ . . .” 
The ventral accessory turbinal does not appear to ossify in the adult Apterya skull. 
There are no ossified turbinals in the other Palwognathe. 
The lachrymal in Casuarius is crescentic in form, with convex border forwards. 
Its upper limb, when visible, is very broad and deeply notched. It forms a broad 
overhanging ledge to the orbit. Its lower limb is flattened from before backwards and 
extends downwards to within a short distance of the quadrato-jugal bar. At the 
junction of the upper and lower limbs it is perforated by a large foramen for the 
passage of the lachrymal duct. In the adult, the inferior inner lateral border is fused 
with the antorbital plate. 
