PLATE X. 



Two views of the pelvis of the Mylodon robustus, rather more than one-sixth the 

 natural size, or on the scale of two and a quarter inches to a foot. 



Fig. 1 . Upper surface of the pelvis with the anchylosed lumbar vertebrae 

 and last dorsal vertebra. 



The proper sacral vertebrae are numbered 1 to 7 ; the three lumbar 

 vertebrae are numbered 8, 9, 10 ; the last or sixteenth dorsal is 

 numbered 11 and d 16. 

 Fig. 2. Hinder surface of the pelvis, showing the form of the outlet. 



a. Anchylosed rib of the sixteenth pair : a style is represented as 

 passing through the interspace between its neck and tubercle, 

 here converted into a foramen. 



b. Superior anterior articular or oblique process of the last dorsal 

 vertebra. 



c. Transverse process of the first lumbar vertebra. 



d. Transverse process of the second lumbar vertebra. These, with 

 the corresponding process of the third lumbar, are developed into 

 a broad thin bony plate confluent with each other, and with the 

 ihac labrum. 



e. Sacro-ischiadic foramina. 



/. Ischiadic tuberosities confluent with the sacrum. 



g. Bony crest formed by the confluent spines of the lumbar and 



sacral vertebrae. 

 h. Canal intercepted by the spinous crest and the obhque or articular 



processes of the sacrum. 

 i. Confluent extremities of the transverse or costal processes of the 

 sacrum, forming the outer boundary of the wider canal between 

 them and the oblique processes. 

 k, k. Foramina for the posterior divisions of the sacral nerves opening 



into the foregoing canal. 

 I, I. Labrum of the ilium bent forwards, 

 vi,m. Acetabula. 



n. Symphysis pubis. 

 0. Obturator foramina. 

 p. Pubic bones. 

 The bones of the Mylodon robustus, figured in Plates XI. to XXII. inclusive, 

 are reduced one-half the natural size. 



