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Transactions of the 
This is followed by the growing basi-occipital ( b . o .) ; this by the 
condyle (o. c.), and this is surmounted by the “ex-” and “ super- 
occrpitals ” (e. o., s. o.). 
My next stage is a nestling of the Carrion Crow ( C . cor one), one 
week old. 
The most noteworthy thing in these further illustrations is the 
great increase of size, every tissue having undergone rapid inter- 
stitial growth ; hut the relative proportion of the various hones and 
tracts of membrane and cartilage is much the same as at the time 
of hatching. 
Certain morphological changes of great importance have never- 
theless occurred, for the “ super-occipitals ” (Plate XXXVII., 
Figs. 1-5, s. o.) have coalesced at the middle, and the “meso- 
ethmoid ” (Figs. 2 and 4, p. e.) has acquired a bony centre. 
The lachrymal (l.) is larger, is creeping up the fore-edge of the 
ecto-ethmoid (Fig. 2) : the “ articulare ” (Figs. 2 and 6, ar.) now 
embraces the internal angular process. The elements of the pos- 
terior sphenoid, and of the auditory capsule, all these are becoming 
more closely related to each other. 
The hyoid cartilages (Fig. 7) are only larger, altogether, than 
in the ripe embryo ; the elements of the mandible (Figs. 2 and 6) 
are now closely similar to what is seen in the adult Lizard or 
Crocodile. 
The fifth stage is that of the young Eook ( C. frugilegus), ready 
to fly. It is replete with interest. 
The basal and lateral elements of the occiput, &c. (Plate 
XXXVIII., Figs. 1, 4, e. o., b. o.) have coalesced ; but the upper piece 
(s. o.) still forms an elegant, distinct keystone above (Plate XXXIX., 
Figs. 1 and 2). The basi-temporals have coalesced with the over- 
lying “ para-basisphenoidal ” ossification, and at their outer angle 
the internal carotids (Fig. 1, b, t., i. c .) are seen entering. 
The fore-part of the “ sphenoidal rostrum ” (r. b. s .) is embraced 
by the forks of the vomer ( v .), and its sides by the “meso-pterygoid 
process” of the pterygoid, and by the “post-palatine processes.” The 
“trans-palatine” (t. pa.) is still solid cartilage, without bony deposit; 
it is a large and well-defined morphological element. 
The grooved upper surface of the vomer receives the thick part 
of the base of the septum-nasi ; this base is then two-winged, and 
these wings are a part of each trabeculas, unaltered in shape although 
coalesced together. In front of this part is the shrinking “ prae- 
nasal rostrum ” (p. n.) which lies between the recurrent ali- nasal 
folds. 
The ali-nasal floor (al. n.), over which lies a “ turbinal,” is seen 
on each side of the base of the nasal septum ; behind, it is conti- 
nuous with the vomer on each side, the moieties of which are grafted 
upon the cartilage. 
