NOTES ON CARBONIFEROUS COCHLIODONTS 33 



teeth of this character have been found in the Burlington limestone. 

 They are usually fragmentary, but fit the posterior teeth of D. 

 spatulatus, and there are no other posterior teeth from that for- 

 mation with which they can be classed. 



Formation and locality: Kinderhook, Burlington, and Keokuk limestones; 

 Illinois, Iowa, and Indiana. Numerous in the Burlington and rare in the Kinder- 

 hook. 



Deltodus attenuates sp. nov. 



(Plate I, Fig. 6) 

 Tooth triangular in outline. The type specimen measures 22 mm along 

 the antero-lateral border, 27™'" along the postero-lateral border; inner margin, 

 i5 mm . Tooth slightly arched longitudinally, little arched transversely. A ridge 

 runs from the acute angle of the posterior border to the anterior border. The 

 tooth slopes down abruptly from this ridge to the postero-lateral border, excepting 

 at the posterior angle, where there is an alation that turns upward. The postero- 

 lateral border is very thin. Toward the anterior border there is no depression, 

 the rest of the tooth being the same height as the ridge. The antero-lateral 

 margin is very thick at the inner end, but thins out toward the outer end. The 

 posterior inner angle is obtuse, the posterior outer angle acute. The surface of 

 the enamel is very finely punctate throughout. 



This species differs from Deltodus angularis (Orthopleurodus car- 

 bonarius) St. J. and W. in being much narrower and thinner, much 

 less arched both longitudinally and transversely, and in the charac- 

 ter of the ridge. 



The type specimen, a posterior tooth from left mandible or right 

 maxilla, is from the Coal Measures near Kansas City, Mo. It is 

 now in the collection of the University of Kansas. 



PLATE 1 



Fig. i. — Psephodus acutus sp. nov. Median tooth of left mandible or right 

 maxillary. 



Fig. 2. — Psephodus legrandensis sp. nov. Dentition of one jaw; anterior 

 teeth restored in outline. 



Figs. 3-5. — Sandalodus alatus N. and W. Fig. 4 shows the alations on both 

 sides of the tooth. Fig. 3 has the alations restored in outline. Fig. 5 shows the 

 characteristic punctation of the teeth. 



Fig. 6. — Deltodus attenuatus sp. nov. Posterior tooth; anterior end and part 

 of alation restored. 



Fig. 7. — Psephodus carbonarius sp. nov. An almost perfect posterior tooth. 



Figs. 8 and 9. — Sandalodus occidentalis Leidy. Fig. 8 shows the characteristic 

 shape of the anterior edge of the teeth of this species. Fig. 9 shows posterior end of 

 tooth; anterior end restored from more perfect specimens. 



