327 
of the cerebrum (fig. 12, @, a) is 2 inches 2 lines; its length is 1 inch 7 lines; its depth, 
or vertical diameter, is 1 inch 1line. The breadth of the rhinencephalon (7) is 8 lines; 
the length of each lobe in advance of the cerebral hemisphere is 24 lines. They are 
relatively less than in Apteryx. 
The hypophysis, as represented by the cast of the “ sella” (ib. figs. 11, 13, y) is of con- 
siderable size; there is an indication of a better-developed pineal gland (ib. fig. 12, p) 
than in the Apteryx. 
§ 2. Trachea of Apteryx, Struthio, and Casuarius. 
In the Apteryx australis the trachea has a nearly uniform diameter throughout its 
extent; the rings, from 120 to 130 in number, are entire and cartilaginous. When the 
windpipe is relaxed the rings alternately overlap, and are overlapped by, each other at 
their sides, appearing to be alternately narrower on one side than on the other; but when 
the tube is stretched this appearance is lost, though not wholly, the rings then showing 
a slight difference of breadth in the axis of the tube at their sides. They become 
gradually smaller in circumference and diameter in the last twenty, which are less 
closely attached together than in the Ostrich and Emu. 
In the trachea of the Cassowary the rings, mostly entire as in other birds, vary in 
depth, ¢. ¢. in the diameter of the hoop parallel with the length of the tube, and they 
correspondingly vary in thickness (Pl. XCII. fig. 5). Their excess in these diameters is 
shown at about one-fourth down the trachea; they become narrowest and thinnest at 
the terminal tenth part of the tube, where a solution of continuity of the ring begins 
to show itself along the mid line of the back part of the tube. The incomplete rings 
of the bronchi resume the dimensions of those at the beginning and migdle of the 
trachea. 
In the Ostrich the bronchial rings are more slender than any of those of the trachea, 
and rapidly diminish in size as they approach the lungs. 
In both Ostrich and Cassowary the tracheal rings examined by me were gristly, or 
were hardened with a very small proportion of bone-earth. 
§ 3. Trachea of Dinornis crassus. 
The more completely ossified state of the tracheal rings of Dinornis has led to their 
preservation in more than one species; and I have received from time to time specimens 
of such rings more or less closely associated with parts of the skeleton, in largest 
numbers with that collection of Dinornis remains obtained by Mr. Walter Mantell 
from the fine dark soil, or morass, at Ruamoa, Middle Island of New Zealand, and pur- 
chased for the British Museum (p. 223). 
In working out this matrix from the base of the skulls of Dinornis crassus, described 
in a former Memoir (pp. 262-284), I detached from beneath the position of the palato- 
nares a group of four bony hoops or rings of an oval form, averaging 9 lines in long 
