PLATE I. 



PAGE. 



Fig. 1. PSEPHODUS OBLIQUUS, St. J. and W <JG 



1 o. Large median tooth, right ramusof lower jaw, viewed from above; 1 lj, do., 

 from inner margin; Ic do., outer margin; I d do., antero-lateral border, 

 showing crenulated coronal fold; 1 e do., postero-lateral border, show- 

 ing broad undulations, Kinderhook; Burlington, Iowa. Coll. Prof. 

 Worthen. 



Fig. 2 a. 6, c, d, e. similar views of a large median tooth, referred to the right ramus of 

 upper jaw. Same formation, locality and collection. 



Fig. 3 a, b, c, d, e. Same views of tooth, left ramus of upper jaw. Same formation, 

 locality and collection. 



Fig. 4 a, b, c, d. Similar views of an elongate, more convex tooth, identified with the- 

 preceding form. Kinderhook upper fish beds; Burlington, Iowa. Coll. 

 Mr. Wachsmuth. 



Fig. 5 a, b, c, d, e. Similar views of a very small, longitudinally abbreviated tooth, re- 

 ferred to the same position upon the jaw as the last, with which it is pro- 

 visionally identified. Same formation, locality and collection. 



Fig. 6. PSEPHODUS ? STMMETEICUS, St. J. and W 71 



6 a. Mandibular tooth, right ramus, seen from above; 6 b do., outline from inner 

 margin; 6 c do., outer margin: t d do., profile outline from antero-lateral 

 border, foreshortened. Kinderhook lower fish bed; Burlington, Iowa. 

 Coll. Mr. Wachsmuth. 



Fig. 7 o. A very small, nearly entire tooth of the left ramus of lower jaw, pro- 

 visionally identified with the last, view from above, enlarged; 7 b do., 

 inner margin; 7 c do., showing outer inrolled margin; 7 d do., profile from 

 antero-lateral border. Kinderhook, upper fish-bed; Burlington, Iowa- 

 Coll. Mr. Wachsmuth. 



