PROFESSOR HUXLEY ON THE OSTEOLOGY OF THE GENUS GLYPTODON. 69 
line of the two anterior sacral vertebree, behind which commences the great sacro- 
coccygeal curve, concave towards the cavity of the pelvis. The lumbo-sacral is very 
nearly as long as the dorso-lumbar region, so that the vertebral column, from the last 
cervical to the last coccygeal, may be said to form two subequal arches with a common 
pier, formed by the proper sacral vertebrae. 
Description of the Plates. 
PLATE IV. 
Figs. 1 & 3. Upper and under views of the skull of the “new specimen” of Glyptodon 
clavipes. 
Figs. 2, 4, & 5. Upper, under, and side views of the hinder part of the skull of the 
“typical specimen” of Glyptodon clavipes. 
All reduced to one-half the natural size. 
PLATE V. 
Fig. 1. Side view of the skull of the new specimen of Glyptodon clavipes. 
Fig. 2. The left half of the mandible of the same, one-half the natural size. 
Fig. 2°. The ascending ramus of the mandible, viewed from behind. 
Figs. 3 & 4. Grinding-surfaces of the teeth, of the natural size. 
PLATE VI. 
Front view, and 
Back view of the skull of the new specimen of Glyptodon clavipes. 
View of the occipital face of the skull of the typical specimen. 
Front view, and 
Upper view of the mandible of the new specimen. 
All reduced to one-half the natural size. 
PLATE VII. 
Figs. 1 & 2. Front and back views of the fragment of the atlas. 
*** The artist has inadvertently inverted each figure, so that the lower 
side of the bone is turned upwards, and vice versa. 
Fig. 3. The trivertebral bone, seen from above. 
Fig. 4. The trivertebral bone, from behind ; d, the first rib, in place. 
Fig. 5. The trivertebral bone, from in front. 
Fig. 6. The trivertebral bone, viewed from the right side. 
Fig. 1. 
Fig. 2. 
Fig. 3. 
Fig. 4. 
Fig. 5. 
