84 PALEONTOLOGY OF ILLINOIS. 



set punctae ; toward the inner margin the enamel layer is undulated 

 by transverse lines of growth. The absence of distinct longitudinal 

 arrangement of the punctte also contrasts with the above named 

 species. A mature individual attains a breadth across the inner 

 margin of 27 m m., and a length along the antero-lateral border of 

 probably 10.5 m m. 



We have thus far failed to recognize other and probably associate 

 forms of the above species, so that it is impossible to say how in- 

 timate its relations are with the teeth that constitute the represent- 

 ative forms of the allied genus Stenopterodus. The general outline 

 and the obliquity of the coronal prominence offer striking resem- 

 blances to Deltoptychius, but the absence of the secondary lobe 

 anterior of the principal prominence precludes its reference to that 

 genus. 



Geological position and locality; Upper Burlington limestone fish- 

 beds; Buffington creek, and Augusta, Iowa. 



VATICINODUS? SIMPLEX, St. J. and W. 



PI. IV, Fie. 22-26. 



Teeth of small size. Maxillary posterior teeth subelliptical in 

 outline. Antero-lateral border somewhat obliquely truncated from 

 the obtuse inner angle forward to point of inrollment ; postero- 

 lateral border very rapidly converging from the sharply rounded 

 posterior extremity toward point of inrollment, forming, an angle of 

 20 to 30 with the opposite border, making a broad gentle arch; 

 basal border channeled and posteriorly produced into a thin rim 

 which extends beyond the limits of the inbeveled coronal border; 

 inner margin in front nearly parallel with the postero-lateral 

 border, strongly and abruptly arched round the base of the coronal 

 ridge to the posterior extremity, basal portion relatively deep and 

 placed in the same plane as the crown from which it is defined by 

 the inbeveled inferior belt of enamel. Coronal region moderately 

 arched in the direction of inrollment, posterior lobe occupying 

 rather less than half the lateral diameter of the crown, very 

 oblique, and sufficiently well-defined in front, moderately arched 

 transversely with a slight depressed belt along the postero-lateral 

 border; anterior portion or neck nearly plain, or very faintly con- 

 vex transversely, with an obscure revolving sulcus margined by a 

 narrow plain belt along the antero-lateral border, in worn 

 examples, even the posterior lobe is imperfectly defined in front 



