No. 5.] 



PARIOTICHUS INCISIVUS COPE. 



241 



brae without ribs. Other than the disappearance of the trans- 

 verse processes and a gradual gain in stoutness, there is little 

 change in the whole series (Fig. 4). 



There are two vertebrae in the sacrum : the first bears a 

 strong rib with an expanded distal extremity as wide as the 

 length of the vertebrae ; the second has a less well developed 

 pair of ribs with the distal extremity hardly broader than the 

 rest of the process (Fig. 5). 



There are two caudal vertebrae attached to the sacrals ; they 

 are much the same in appearance as the others, and have short 



Fig. 4. — Dorsal view of anterior dorsal series. 



Fig. 5. — Dorsal view sacral vertebrae. The 

 surfaces of vertebrae are restored. 



strong ribs attached. A 



small fragment contains 



three caudals near the end 



of the tail ; they show that 



the dorsal spines were much 



longer than in the dorsal 



region, and that there were rather long and slender ribs 



anchylosed to the vertebrae. Their size seems to indicate 



that the animal had a rather long tail. 



The clavicles and the interclavicle are large and well devel- 

 oped, having much the appearance of the same bones figured by 

 Cope in ParioticJius aguti (4) (PI. VII, Fig. 2). The clavicle is 

 there designated the episternum. The anterior end of the inter- 

 clavicle is diamond-shaped in outline ; the lateral parts of the 

 head underlie the ventral ends of the clavicles ; they have a 

 rugose sculpture of fine lines. The posterior portion is con- 

 tinued into a cylindrical process at least twice as long as the 

 rest of the bone ; its distal end is somewhat rugose. 



