52 



University of California Publications. 



[Geology 



as thin as on the first, and there is a minute rudiment of an ana- 

 pophysis on one side only. The neural spine is rather broad and 

 high, bnt is unfortunately not complete. The fourth vertebra is 

 shorter than the others, the metapophyses are broader, the in- 

 ferior surface is not distinctly keeled, and the thin transverse 

 processes are well developed though broken distally. This vertc- 



18 



Fig. 17. Archaelurus debilis major. Lumbar vertebrae. No. 1680. Mid- 

 dle John Day, Turtle Cove, John Day Valley, Oregon. X %. 



Fig. 18. Archaelurus debilis major. Caudal vertebra. No. 110. Middle 

 John Day, Blue Basin, John Day Valley, Oregon. X %. 



bra is peculiar in that it lacks a. neural spine. In the place of the 

 spine there is a very indistinct ridge not exceeding a millimeter 

 in height. This last vertebra is presumably the seventh lumbar, 

 the others being the sixth, fifth, and fourth. This vertebra does 

 not agree in form with the seventh lumbar of Archaelurus debilis 

 described by Cope, which had a high neural spine. 



With the complete tibia and calcaneum, No. 110, referred to 

 Archaelurus, there is a large but slender caudal vertebra (text- 

 figure 18) which must have been situated near the middle of a 

 long slender tail. 



