PLATE XI. 



PAGE. 

 DELTODOPSIS AFFINIS, St. J. and W 160 



Fig. 1 a. Mandibular posterior tooth, left rarnus, view from above; 1 I, do., showing 

 antero- lateral border: 1 c, do., transverse profile from inner margin. 

 Warsaw limestone; Warsaw, 111., Prof. Worthen. 

 DELTODOPSIS ST. LUDOVICI, St. J and W 161 



Fig. 2 a. Mandibular posterior tooth, left ramus, view from above, outer extremity 

 restored in outline; 2 I, do., longitudinal profile from antero-lateral 

 border; 2 c, do., postero-lateral border; 2 d, do., transverse profile from 

 inner margin: 2 e, do., inferior surface. St. Louis formation; Pella, Iowa, 

 0. St. John. 



Fig. If. Tooth of the same form, right ramus. Same formation, locality and col- 

 lection. 



Fig. 3 a. A smaller perfect example of the same form, right ramus, from above: 3 b, 

 do., antero-lateral border. Alton, 111., Prof. Worthen. 



Fig. 4 a. Maxillary posterior tooth, right ramus, view from above, inrolled extremity 

 restored in outline; 4 b, do., antero-lateral border; 4 c, do., the same in 

 longitudinal profile; 4 d, do., postero-lateral border; 4 e, do., transverse 

 profile from inner margin; 4 f. do., inferior surface. St. Louis formation; 

 Pella, Iowa, Mr. St. John. 



Fig. 5 a. Same form, left ramus, seen from above; 5 b, do., antero-lateral border. 

 Alton, 111., Mr. Van Home. 



Pig. 6 a. Mandibular median tooth, left ramus, view from above, enlarged and par- 

 tially restored at the outer extremity; 6 5, do., postero-lateral border; 

 6 c, do., antero-lateral border. Pella, Iowa, Mr. St. John. 



DELTODOPSIS ANGUSTUS, (N. and W. sp.) 163 



Fig. 7 a. Maxillary posterior tooth, left ramus, view from above; 7 b, do., longitudinal 



profile from antero-lateral border; 7 c, do., transverse profile from inner 



margin. Chester Limestone; Chester, Prof. "Worthen. 

 Fig. 8 a. Same form, right ramus, from above; 8 b, do., antero-lateral border. Same 



formation, locality and collection. 

 Fig. 9 a, Mandibular posterior tooth, right ramus, from above, outer margin restored 



in outline; 9 6, do., antero-lateral border; 9c, do., transverse profile 



from inner margin. Same formation, locality and collection. 

 Fig. 10 a. Same form, left ramus, from above, restored in outline. Same formation, 



locality and collection. 



DELTODOPSIS? CONVOLUTUS, St. J. and W 165 



Fig. 11 o. Mandibular posterior tooth, left ramus, view from above; 11 b, do., longitu- 

 dinal profile from the antero-lateral border; 11 c, do., postero-lateral 

 border; 11 d, do., inferior surface; 11 e, do., transverse profile from the 

 inner margin. Upper Burlington limestone, fish-bed; Louisa county, 

 Iowa, Mr. Springer. < 



Fig. 12 a, b, c. d, e. Similar views of a small example of the same form, right ramus. 

 Same formation, locality and collection. 



DELTODOPSIS? INFLEXUS, St. J. and W 167 



Fig. 13 a. Mandibular posterior tooth, right ramus, from ahove, outline restored; 

 13 b, do., transverse profile from inner margin; 13 c, do., outer margin; 

 13 d, do., longitudinal profile from the antero- Jbteral border, articular 

 edge mutilated; 13 e, do., postero-lateral border. Keokuk limestone; 

 Warsaw. 111., Prof. Worthen. 



