584 



shows that in the structure of the bony palate, as in some other 

 parts of the skull, the Dicynodon combines Crocodilian with Chelo- 

 nian and Lacertian characters. 



The specimen above described was obtained by H.R.H. Prince 

 Alfred, from the Karoo beds, in the district of Graaf Reinet, South 

 Africa. 



The author next proceeds to describe the pelvis of a Dicynodon 

 equalling in bulk the D. tigriceps, and most probably belonging to 

 that species. It includes, with five sacral vertebrae, the last of those 

 of the trunk which supported free ribs, showing that there are no 

 vertebrae having the character of lumbar ones in Dicynodon. The 

 length of the six successive centrums was 1 foot 2 inches. The ribs 

 of the first sacral vertebra resemble in size and shape the human 

 scapula, but are much thicker ; their expanded terminations, 6 inches 

 in breadth, underlap or pass anterior to the iliac bones, to which this 

 rib has been attached by syndesmosis. The ribs of the succeeding 

 sacral vertebrae are shorter and thicker, and abut against the ossa 

 innominata, as far back as the ischial tuberosities. The ilium, 

 ischium, and pubis have coalesced to form one bone, as in some 

 lizards and in mammalia ; and, as in the latter class, the symphysis 

 at which the ischio-pubic portion of each os innominatum joins its 

 fellow is continuous ; the pubic symphysis is not separated from the 

 ischial symphysis. But ossification has advanced further than in 

 any mammal, to the complete obliteration of the obturator foramina, 

 which in most reptiles are represented by very wide vacuities. The 

 pubic bones show an oblique perforation near the acetabulum, homo- 

 logous with that which co-exists with large obturator openings in 

 most lizards. The brim of this singularly massive pelvis measures 

 10 inches in antero-posterior, and 1 1 inches in transverse diameter : 

 the outlet measures 4 inches in antero-posterior, and 9 inches in 

 transverse diameter. 



In the comparison of this, at present, unique type of pelvic struc- 

 ture, it is interesting to observe, in connexion with the mammalian 

 tusks in the skull, a mammalian condition of the symphysis pubis, 

 and also a mammalian expansion of the iliac bone. In the number 

 of sacral vertebrae Dicynodon resembles the Dinosaurian reptiles, as 

 well as some mammalia ; and hence it may be inferred that, like the 

 Megalo&aurus and Iguanodon, a heavy trunk was in part supported 



