PROFESSOR HUXLEY ON THE OSTEOLOGY OE THE GENUS GLYPTODON. 57 
described in the new specimen, are visible, attached to the under surfaces of the nasal 
bones. 
The inner surface of the right lateral portion of the ethmoid is marked by obliquely 
diverging ridges of bone, with which the plates of the inferior spongy bone were doubt- 
less connected. 
By combining the new specimen with this it is easy to ascertain approximatively the 
length of the cribriform plate. The former specimen, in fact, is broken through at a 
distance of six inches from the anterior end of the snout, but its posterior face does not 
exhibit any notable part of the anterior wall of the cranial cavity. The same distance 
(6 inches), therefore, measured off upon the roof of the type skull, should give the 
position of a line beyond which the cribriform plate certainly did not extend anteriorly. 
From the point thus defined to the anterior edge of the presphenoid is a distance of 
1*75 inch, which must therefore represent the maximum length which the cribriform 
plate could have attained. The distance from the anterior edge of the presphenoid to 
the level of the posterior margins of the occipital condyles is 4*5 inches. The cribriform 
plate is rather shorter in proportion to the base of the skull in the Glyptodon than in 
the ordinary Armadillos, and its anterior part is situated far further back in relation to 
the antorbital processes. 
The proper cranial cavity, or brain-case, is small when compared with the whole size 
of the skull, if the chambers which lodge the olfactory bulbs are left out of considera- 
tion. It is in fact only 4*5 inches long, 2*5 inches wide at widest, and about If inch 
high at highest. Its greatest width is situated beneath the occipital ridge, whence it 
narrows towards the olfactory outlet, which is about 1*25 inch wide. The immediate 
side walls and roof of the fore part of the cranial cavity are formed by a very thin inner 
table of bone, separated by a wide air-chamber from the denser and stouter outer table. 
This air-chamber does not appear to extend back beyond a transverse line connecting 
the two glenoidal facets. 
Mr. Flower has obtained a cast of the cranial cavity, from which one is enabled to 
form an idea of the shape and size of the brain. The proportionally large cerebellum 
exhibits a prominent vermiform process, and is completely uncovered above by the 
cerebral hemispheres. The latter are quite smooth, and their upper contour is much 
arched, while their sides are flattened, and approach one another anteriorly. The 
absence of convolutions in the brain of so large an animal, together with the small 
absolute mass of the organ, leads one to suspect a great absence of intelligence in the 
Glyptodon. 
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