PLATE IV. 



Fig. 1. Trachodon (^Pleropelyx) marginatus, Lambe, outer side of the same mandibular ramus figured 

 on plate III ; one-half the natural size. Page 73. 



Fig. 2. Trachodon (Pleropelyx) altidens, Lambs, outer side view of left maxilla, one-half natural size. 

 The speciman was drawn upside down so as to hove a better light on the teeth. Page 76. 



Fig. 3. Inner view of the same specimen, with part of the inner wall removed to show successional teeth ; 

 one-half natural size. 



Fia;. 4. Two teeth from the same specimen, showing the characteristic border sculpture, with the crown 

 of the worn tooth restored, in dotted outline, to show the proportion of length to breadth ; twice 

 the natural size. 



Fig. 5. Trachodon (Pleropelyx) marginatus, Lambe, outer view of apical part of crown of tooth from the 

 maxilla represented on plate V, for comparison with fig. 4; twice the natural size. Page 74. 



Fig. 6. Trachodon {Pteropelyx) marginatus, crown of one of the testh of the ramus shown in fig. 1 of 

 this plate and fig. 1 of the preceding plate; twice the natural size. Page 73. 



Fig. 7. Pleropelyx grallipes, Cope, crown of tooth of lower jaw, to show border sculpture ; twice the 

 natural size. Introduced for coiiparison. Page 77. 



i 

 /J grinding surface of teeth ; a, facet for jugal. 



