EXPLANATION OF PLATE XXIX. 



Vertebra} of Ziodon dyspclor, from Butte Creek, one-half natural size. They are selected from various 

 pointB in the column, the best-preserved being preferred ; most of the dorsal and caudal vertebra 

 are omitted. 



Fig. 1. Atlas and axis from the side : a, centrum of atlas ; 5, neurapopbysis ; c, hypapopbysis ; d, centrum 

 of axis, free hypapopbysis omitted (see Plate xxviii, fig. G). 



2. Last cervical. 



3. A posterior dorsal. 



4. A lnmbo-sacral, with its posterior face upward, with ueural arch on right, and diapopbysis on 



left side. 

 Figs. 5 to 6. Caudal vertebra. 



