94. Dr. Burmeister on the Species of Glyptodon 
which receives the ribs. But below the lumbar canal, there are’ 
on each side some rather large foramina for the nerves which- 
issue from this part of the myelon. I have counted in the two 
lumbar canals which are in the Museum, belonging to Glyptodon. 
clavipes, six of these foramina, and in the same canal of the G. 
spinicaudus seven, which proves that the number of vertebrz 
united in this canal are six in the first species and seven in the 
second. There are probably corresponding differences in the 
anterior part of the vertebral canal of the two species, that of 
the G. clavipes being much larger and consequently more 
numerous in the vertebra. The last part of the lumbar canal 
immediately unites with the sacrum without any articulation ; 
the two appear to be the same bone. 
The os sacrum is formed of nine vertebre united in one solid 
mass, which is broad and thick at the commencement, thin, long, 
and high in the centre, and thick with two long prolongations, 
one on each side, at the end. The first part is composed of 
three rather short vertebrae, which unite forward with the pelvis, 
and constitute with it a very high crest, on which the shell of 
the animal is supported. The second part is composed of five 
rather long vertebre, and is in the figure of a curved tube, with 
a high crest on its upper part. Five foramina on each side of 
the tube, for the nerves of the myelon, indicate the number of 
vertebrz in this part of the sacral bone. At the end, it extends 
at its base into a solid and thick mass, which assumes the form 
of the body of a vertebra, and is actually the last vertebra of 
the sacral bone. On each side of it a horizontal prolongation 
extends, smooth and broad, which corresponds to the transverse 
process of the vertebra, and by this prolongation the os sacrum 
unites for the second time with the pelvis. Another small pro- 
longation of the penultimate vertebra also unites with this hori- 
zontal branch. The sacral bone of the Armadillos is formed in 
the same manner, especially that of the Mataco. 
The pelvis is the largest part of the skeleton, and is of a very 
peculiar form. Its thickness is caused by the fact that the whole 
weight of the shell of the animal is superimposed on it, as-it is 
the only bone which unites immediately with the shell. For 
this reason the pelvis extends forward and backward into two 
eveat perpendicular ale which gradually augment into very broad 
and strong crests, armed with many obtuse tuberosities, which 
impinge upon other similar ones on the inferior surface of the 
shell, having between them large cushions of an elastic cartila- 
ginous substance, to sustain the weight of the shell more easily, 
and to permit its more facile elevation during the movement of 
the body. The anterior prolongations are placed across the spine, 
and belong to that part of the pelvis known by the name of the 
a a ee 
