EXPLANATION OF PLATE X. 



Figures i, 2, 3, 4, and 6, natiual size. 

 Ithygrammodon CAMELOIDES. 



Fig. I. — Left premaxillary, inner view. 



Fig. 2. — Left premaxillary, outer view. 



Fig. 3. — Right maxillary and premaxillary, outer view, premolar, with dotted 

 outline indicating its probable position. 



Fig. 4. — The premaxiUaries in position (probable), view from above, show- 

 ing size and position of the incisors. Dotted lines indicate the premaxillary 

 spine (estimated). 



Procamei.us occidentalis, Cope, (See Wheeler's Survey, vol. iv., Plate 

 LXXVII.) , 



Fig. 5. — Part of right maxillary and premaxillary, showing single incisor 

 with rudimentary alveolus for a second. 



Pkotolacis ? Cope. (See Wheeler's Survey, vol iv., p. 343.) 



Fig. 6. — Right maxillary and premaxillary. (This has never been drawn 

 before, and was kindly lent to us for this purpose by Prof. Cope.) 



Camelus bactrianus. Modern camel. 



Fig. 7. — Right maxillaries, one half natural size. 



