222 
Transactions of the 
membranous interorbital space (i. o. s.). The “nasals” (Figs. 3 
and 4, n.), the frontals (/.), the parietals and squamosals (Figs. 
2 and 3, p. sq.), are now well demonstrable ; but the great 
“ fontanelle ” ( fo .) occupies most of the cranial roof. The second 
pair of prse-oral facial bars are undergoing rapid development ; at 
first delicate crescentic bars of soft mother-cartilage, or indifferent 
tissue, they are now partly true cartilage, but principally bone. 
Behind ( — above) the pterygoids fit by a cup to a ball on the fore-face 
of the pier of the nest arch, the quadrate, and then, converging to 
the mid-line, they send a “ meso-pterygoid process ” over the upper 
edge of each palatine. This process afterwards becomes a separate 
bone. 
Where the palatines {pa.) are bowed out behind, they send out- 
wards a triangular plate, which, not becoming infected by the bony 
matter of the main bar, develops rapidly into hyaline cartilage, to 
have, afterwards, its own endosteal centre — the “ trans-palatine.” 
Two splints are seen on each side, belonging to the pterygo- 
palatine arch. These are the very small iclitlnjic maxillaries {mx.}, 
and the slender “jugals” (J) which clamp the quadrate without 
the intervention of a “ quadrato-jugal,” as in many birds. The 
retral process of the maxillary (maxillo-palatine of Huxley) can 
already be seen passing towards the mid-line, above the palatines. 
The hyoid arch, well developed as to cartilage, but with no 
bony deposits, was not wholly worked out in this stage. It will be 
described in the next. 
But the mandible is now very instructive. Seen on the inner 
side (Fig. 5), the dentary ( d .) is seen to have surrounded all but 
the inner face of Meckel’s cartilage {ink.) in front ; farther backwards 
the most splint-like of the splints — the splenial {sp.) — is now evident, 
and the coronoid {cr.), the “angular” {ag.) } and the surangular 
(s. ag.), are growing rapidly ; the two latter are shown in relation 
to the articular cartilage {ar.) in Fig. 6. Ossification had com- 
menced in the proximal portion of the rod. The articular region 
{ar.), which, as seen from below (Fig. 6), sends backwards the 
“ posterior angular process,” and inwards the “ internal angular 
process.” This latter is the otherwise-used symmorph of the 
“ Manubrium Mallei ” of Man. 
My next stage is supplied by the ripe chick of a Carrion Crow 
{C. corone, Plate XXXV., Fig. 7, and Plate XXXVI., Figs. 1-6). 
The process of development during the last five or six days 
of incubation is very rapid, and indeed very rapid is the whole 
process of growth in these high, noble, hot-blooded birds. The 
study of their growth and metamorphosis, as compared, not only 
with that of a Beptile or Fish, but even with that of the young of 
the slow-growing “ Praecoces,” suggests the possibility of a com- 
promise between the doctrine of Development and that of Creation. 
