NOTES ON SOME CARBONIFEROUS COCHLIODONTS 

 WITH DESCRIPTIONS OF SEVEN NEW SPECIES 



E. B. BRANSON 



University of Chicago 



The following article is the result of the writer's study of the teeth 

 of the genera Cochliodus, Psephodus, Sandalodus, and Deltodus, in 

 the collection of Walker Museum at the University of Chicago. In 

 the collection are several hundred specimens of the teeth of Sandalodus 

 and Deltodus, and more than fifty of Cochliodus and Psephodus. 



The writer is under obligation to Dr. Stuart Weller for the privilege 

 of studying the collection at Walker Museum, and to Professor C. E. 

 McClung for the loan of specimens from the Kansas University 

 Museum. Acknowledgment is due Professor S. W. Williston and 

 Dr. Stuart Weller for helpful suggestions during the investigation. 



Psephodus Agassiz 



Cochliodus Agassiz, 1838 (Recherches Poissons fossiles, Vol. Ill, p. 174). 



Cochliodus Portlock, 1843 (Geological Report on Londonderry, Plate XIV, Fig. 4). 



Cochliodus McCoy, 1855 {British Paleozoic Fossils, p. 622). 



Psephodus Agassiz, 1859 (MSS in the Enniskillen Collection). 



Psephodus Morris and Roberts, 1862 (Quarterly Journal 0} the Geological Society, 



Vol. XVIII, p. 101). 

 Aspidodus Newberry and Worthen, 1866 (Paleontology of Illinois, Vol. II, p. 92). 

 Taeniodus St. John and Worthen, 1883 (ibid., Vol. VII, p. 75). 



A jaw of Psephodus with four teeth in place is preserved in Walker 

 Museum at the University of Chicago. The full dentition of the jaw 

 is probably not present, the front teeth having their anterior margins 

 thick and truncated, as for articulation with other teeth. The missing 

 anterior teeth were probably triangular in form and considerably 

 smaller than those with which they articulate, but no place remains 

 on the jaw for the helodoid teeth which have been so generally con- 

 sidered as forming a component part of the dentition of this genus. 



The history of the belief in the association of helodoid teeth with 

 the large plates on the jaw of Psephodus is interesting and is briefly 

 sketched below. 



