24 



E. B. BRANSON 



on the same jaw with Cochliodus teeth furnishes little evidence to 

 support that hypothesis. The teeth are not in position, and they 

 have the appearance of having been accidentally associated. Owen 

 has shown 1 almost beyond question that Cochliodus had only three 

 teeth on each ramus of the jaw, and more evidence than a few Helodus 

 teeth found preserved in close association with Cochliodus teeth is 

 necessary to demonstrate that they belonged in the same mouth'. 

 Thus it seems probable that in Cochliodus as well as in Psephodus 

 no helodoid teeth were present in the dentition. 



Psephodus legrandensis sp. nov. 



(Plate I, Fig. 2) 

 A small species. Median tooth 5 mm broad, 8 mm along inner margin, 5 mm 

 along outer margin. Inner posterior angle acute and produced backward; outer 

 posterior angle obtuse, rectangular on both sides in front. Tooth strongly 

 enrolled transversely, not arched longitudinally. Inner margins of the two median 

 teeth parallel to each other when in position on the jaw, and approaching very 

 closely on the median line. Posterior teeth subpentagonal in outline, n mm from 

 posterior inner angle to anterior angle of outer edge, 6 mm along articular edge in 

 median line, 8 mm along articular edge for anterior tooth. Teeth strongly arched 

 longitudinally, little arched transversely, not ridged or furrowed. Enamel every- 

 where finely punctate. Edges not crenulate. 



The posterior teeth of this species are readily distinguished from 

 P. crenulatus, P. obliquus, and P. placenta by their smaller size, 

 comparative narrowness, and greater longitudinal arching. The 

 median teeth are more strongly enrolled transversely and propor- 

 tionately narrower than those of the species above mentioned. The 

 median teeth are distinguished from those of P. acutus by their smaller 

 size, greater enrollment and the posterior angle being much less 

 produced. 



Formation and locality: Kinderhook limestone; Legrand, Iowa. 

 Paleontological Collection, Walker Museum, No. 10038. 



Psephodus acutus sp. nov. 



(Plate I, Fig. 1) 

 Type and only specimen observed a median tooth. Measurements: io mm 

 along the inner margin, 5 mm along the outer margin, 7 mrtl along the posterior 

 articular edge, 6 mm along the anterior articular edge. Tooth not arched longi- 

 tudinally, considerably enrolled transversely. Outer and inner margins parallel. 



1 Geological Magazine, 1867, pp. 59-63. 



