1897.] NEW YORK ACADEMY OF SCIENCES. 297 



vertically and laterally. One larger tooth in my collection 

 shares these characters except that the root is relatively longer 

 and I am inclined to think it is an old and worn specimen, but 

 the discovery of others ma}- possibly show that it is only mature. 

 All these teeth differ from those of D. jirincejjs in being broader 

 and lighter, the crown lower and flatter ; the anterior lace of the 

 crown in D. princeps being strongly arched laterally and some- 

 times vertically. 



In form these teeth resemble most those of D. infiexus, N. & W. 

 from the Chester limestone, but in that species the anterior face 

 of the crown is almost at right angles with the vertical, present- 

 ing a flat top by which the summit of the tooth is much 

 thickened. 



Formation and locality, St. Louis limestone, Alton, 111. Type 

 specimens in the cabinet of the Columbia Universit}-. 



Deltodus grandis, N. & W. 



In the second volume of the Report of the Illinois Geological 

 Survey (p. 101) was described a large Cochliodont tooth, to 

 which the above name was given. In the seventh volume of the 

 Report (p. 186) Messrs. St. John and Worthen, referring to 

 Sandalodus leevissimns^ unite with it S. grandis, N. i: W. 

 Against this view I have no facts to offer, and cheerfully con- 

 cede that the large amount of new material in the possession of 

 Messrs. St. John and Worthen made them better judges in 1883 

 than we were in 1866 as to the relations of these closely allied, 

 if not identical species, but I must protest against the union of 

 Deltodus grandis with them. Within the last twenty years I 

 have obtained a large number of teeth which are certainly iden- 

 tical with that named b^^ Mr. Worthen and myself, D. grandis. 

 In the light of that material it is impossible for me to accept 

 the view that this species should be united with Sandalodus. 

 The teeth we have called Deltodus grandis are, in my judgment, 

 typical representatives of the genus, and if it should be proved 

 that thej' were once associated with such teeth as those named 

 Sandalodus laevissinius, then the genus Sandalodus must be 

 abandoned. Yet the proposed union of the two genera seems 

 to me highly improbable from the fact that in man}' localities 

 and formations the teeth called Deltodus are not uncommon, 

 while no straight teeth, like the type species of Sandalodus^ are 

 present. Nothing but the evidence of these diverse forms of 

 teeth found in apposition and plainly the parts of one dentition 

 could persuade me that they are not generically different. 

 Messrs. St. John and Worthen had no such proof, on the con- 



