32 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 5 
din. vertically. This is reaily part of an imperfect orbit, and in the 
upper half of each side is a distinct lachrymal gland. 
On the inner aspect of the cranial floor, the arrangement of 
cranial nerves and foramina is normal in the occipital and otic 
regions. In the anterior part, the absence of eyes and nose makes 
the arrangement peculiar. Immediately behind the region of the 
imperfect orbit already mentioned is an elevated median ridge 
running half-way back the cranial floor. This is found to be a 
mass of adipose tissue in which are embedded a number of bundles 
of muscular tissue, representing the ocular muscles, and in the 
centre a small rounded fibrous structure, probably the tissue which 
should have formed the sclerotic. Into this mass of orbital tissues 
can be easily traced the 3rd, 4th, and 6th nerves, and the orbital 
branch of the 5th, the latter passing to the lachrymal glands and 
forming two supra-orbital nerves. 
The median ridge of orbital tissues is roofed by two small bones 
and by a fibrous band connecting them. The anterior is a small 
triangular cartilaginous bone, articulates with the frontal, and pro- 
bably represents the fused orbito-sphenoids. The posterior roofing 
bone is dagger-shaped, articulates with the alisphenoids, and is 
probably the rudimentary basisphenoid. The alisphenoids, which 
are well-developed, articulate with the basioccipital and with each 
other posteriorly, and on the under side are in contact with the 
united pterygoids. The palatines are united, and, while fairly 
normally formed in the palatal region, send a broad plate upwards 
and backwards. occluding what ought to have been the posterior 
nares, and there is developed forwards a median plate in the region 
where the vomer would have been expected. 
With regard to the brain, the medulla, cerebellum, and midbrain 
are normally developed. Anteriorly development has stopped in 
the region of the conario-hypophysial tract. I fail to detect the 
presence of the pineal body and of the anterior quadrigeminal 
bodies, while the posterior lobes of the corpora quadrigemina 
appear to be enlarged. To the under surface of the anterior part 
of the brain is attached, apparently only by pia mater, a rounded 
body about the size of a pea, which I believe to be the anterior 
lobe of the pituitary body. In short, the brain is well-formed, 
except that the anterior primary vesicle has not given rise to 
ocular vesicles, cerebrum, or olfactory lobes, as is normally the case. 
