(82) 
smaller one behind, stretching upwards in the temporal groove and 
separating the foramen ovale from a large bipartite opening at the 
border of the orbita, which represents the united foramina rotunda, optica 
and spheno-orbitalia. In O. the first mentioned of these apertures is 
separated from the two following by a short bone-column. 
At the ventral side of this temporal palatine-wing in E. we notice 
the front end of a tiny canal, which may possibly represent the 
homologue of the well-developed canalis pterygoideus seu vidianus 
of O., this latter running longitudinally along the margin of the 
palatine-plate, between for. ovale and for. rotundum. The difference 
is explained by the occurrence of a large artery in O., branching 
off from the carotis interna, crossing the tympanic cavity externally 
to the stapes, and entering the vidian canal to reach the orbital 
cavity. This artery, called art. stapedia by TANDLER, is absent in 
E., where the orbits are provided with blood by the carotis externa, 
but perhaps the smali artery occupying the above-mentioned tiny 
canal is the last remnant of the art. stapedia. 
IL. Sphenoid. 
The corpus sphenoïdei in E. appears iong and slender, owing to 
the want of connection with ali-sphenoïdea (alae magnae). It shows a 
concave ventral side, caused by its curving down at both sides in 
slightly elevated but very elongated pterygoidprocesses. At its hinder 
margin it is pierced by the foramina carotica, and laterally to these 
it is provided with backward prolongations of the processus ptery- 
goïdales, viz. the spinae angulares. These latter are much more developed 
in O., where they extend over the ventral surface of the petrosa. 
In this animal they form a narrow partition dividing the foramina 
ovalia from the choanae, whereas in E these two are separated 
from each other by the whole diameter of the pterygoids, which also 
hide the spinae angulares under their projecting median edge. The 
sella turcica of O. is much more elongated in a sagittal direction 
than that of E. This contrasts with the extraordinary development 
in the latter animal of the lamina cribrosa ethmoïdei, which totally 
apchyloses with the sphenoid. In O. no trace of such a cribrous plate 
can be detected. 
The space of the ali-sphenoids is occupied in E. by thin bony 
plates, separated by suture from all the surrounding bones: the 
basi-sphenoïd as well as the others. These plates ossify at a very 
late period, so late indeed that even in the almost adult skull a 
large fontanella is found in this spot, leaving the for, ovale not 
