UPPER CRETACEOUS MULTITUBERCULATA loi 



As was noted by Osboni (1893, p. 313), the single specimen on which this genus 

 rests is not separable from Mettisco'cssus. If synonymy were proven, Paronycliodon 

 would become the correct name of the genus, but there is so much doubt as to the age 

 and relationships of this single specimen that the matter of synonymy must be left in 

 abeyance for the present. 



Paronychodofi lacustris Cope 1876 

 1876. P. lacustris, Cope, Proc. Ac. Nat. Set. Pkila., 1876, 256. 



Type.— Amer. Mus. No. 3970 {Cat. Fossil Ref tiles). Isolated lower incisor. 

 Horizon and Locality. — From the Judith River region, Montana. Said by Cope 

 to be from the Fort Union, probably Hell Creek. 



Diagnosis. — Sole species now referred to genus. Material inadequate. 



This was actually the first Cretaceous mammal to be described, but its true char- 

 acter could not then be appreciated and it was referred to the Dinosauria. Not until 

 Osborn's work of 1893, after numerous other Cretaceous mammals were known, was 

 its mammalian nature recognized. The age is doubtful, but it is probably from the 

 Hell Creek beds, the Lance equivalent. This would be in keeping with its probable 

 synonymy with Menisco'essus. Although said to be from the Judith River, it was ap- 

 parently not derived from the Judith River beds. These were known to Cope, and the 

 present specimen was referred not to them but to the higher "Fort Union," which then 

 included the Hell Creek in this area. 



Meniscoessus Cope 1882 

 1882. Menisco'essus, Cope, Am. Nat., XVI, 830. 



Definition. — Lower incisor deep, strongly compressed laterally, with enameled 

 crown, strongly grooved on inner and outer faces. P3 present. P4 relatively short and 

 high, with not over nine serrations. Molar cusps very strongly crescentic. M2 elongate. 

 Doubtfully associated posterior upper premolars short, high, with four or five cusps in 

 main series and a single supplementary external basal cusp. Jaws relatively short and 

 robust. Species larger than those of Cimolomys. 



Type. — M. conquistus Cope. 



Distribution. — Lance formation, Wyoming, South Dakota. Hell Creek beds, 



Montana. 



Included Genera 



1889. Difriodoti, Marsh, Amer. Jour. Sci. (3) XXXVIII, 85. Type: D. robustus Marsh. 

 1889. Tripriodon, Marsh, Amer. Jour. Sci. (3) XXXVIII, 86. Type: T. coelatus Marsh. 

 1889. Selenacodon, Marsh, Amer. Jour. Sci. (3) XXXVIII, 86. Type: S. fragilis Marsh. 

 1889. Halodon, Marsh, Amer. Jour. Sci. (3) XXXVIII, 87. Type: H. sculftus Marsh. 

 1889. Oracodon, Marsh, Amer. Jour. Sci. (3) XXXVIII, 178. Type: O. ancep Marsh. Doubt- 

 fully included. 



