1897.] NEW YORK ACADEMY OF SCIENCES. 285 



The figure and description of G. elegans published in the 

 fourth volume of the report of the Geological Survey of Illinois 

 are wrong in representing the exterior lateral cones as much 

 larger than the median. The specimen upon which the descrip- 

 tion was based was imperfectly preserved and abnormal. Better 

 specimens recently received from Mr. McAdams, of Alton, 111., 

 show that the teeth are more robust, less compressed and have 

 the lateral denticles more nearly equal in size than was the case 

 in the type specimen. 



Formation and locality, Kinderhook group, Burlington, Iowa. 

 T^'pe in the cabinet of Mr. William P. E. Gurley, of Danville, 111. 



Cladodus mortifer, N. &. "W. 

 PI. XXII., figs. 2, 2a. 



In the second volume of the Geological Survey of Illinois were 

 published a description and a figure of a very imperfect tooth 

 which was taken as a type of this species. Since that time 

 numerous specimens have been found in the Coal Measures of 

 Illinois and Indiana and I am now able to give a figure of one 

 of these which is practically complete and affords a far more 

 satisfactory view of the species. The restored figure, 5, plate I. 

 of the volume cited accurately represents the normal form, but 

 the surface markings which are quite strong are not seen in it. 

 Both the central and lateral cones are conspicuously striated and 

 the former is much flattened and sharply double-edged so as to 

 penetrate flesh with greater facility. The lateral cones are rela- 

 tively large, the base broad and strong so that it has a decidedly 

 bristling and hostile appearance. A diagnostic mark of the 

 species is formed by two raised pads or cushions on the upper 

 surface of the base; these are irregularly rounded, about a 

 quarter of an inch in diameter, and are situated about opposite 

 the internal pair of lateral cones. 



The specimen now figured is from the Lower Coal Measures 

 near Newport, Indiana. 



Genus Oracanthus, Agassiz. 

 Oracanthus vetustus, pi. XXII., fig 3. 



In 183.3 in his " Poissons Fossiles " Professor Louis Agassiz 

 described and figured, under the name of Oracanthus, certain 

 broad, compressed Elasmobranch spines found in the Carbon- 

 iferous limestone of England and Ireland. Of these he formed 

 four species, 0. Milleri, 0. minor, 0. pusfulosus and 0. con- 

 Jluens. Of these the first three were described, the last mentioned 



