376 



JIONOG RAPES OF NORTH AMERICAN RODENTIA. 



Genus PANOLAX Cope. 



ruKolax Coi'K, Proc. Acad. Nat. Sci. Fliila., 1874, 151. 



" Molars prismatic, transverse, except tlic first and last, each divided l»y 

 n jdatc of enamel exteiuling transversely from the inner side. Anterior niular 

 longitudinal; posterior molar composed of two columns. 



"This genus is represented by numerous teeth and portions of tho 

 cranium. It evidently belonged to the LeporidtB, and is allied both to Lfjtus 

 and Palaolagus. As the teeth are mostly separate, it is not easy to determine 

 which is the posterior and whicii the anterior molar. Ju<lgingby the analogy 

 of the known species, the determination as here made is correct. ShouKI the 

 relations be reversed, the species will be referred to Paltzolagusr — (Cope, 1. c.) 



From the nature of the materials, the character of this genus cannot well 

 be determined. Its admission here is of course provisional only. 



PANOLAX SANCTiE-FIDEI Cope. 



Panohx mnctw-JIM Cope, Proo. Aca<l. Nat. Sci. Phila., 1874, 1 51. 



m 



This species is known only from several detached molar teeth, found in 

 the Santa Ft5 marls. These marls have been regarded by Dr. Hayden as of 

 late Tertiary age, and are found, according to Professor Cope, to contain the 

 remains of numerous Pliocene genera, which show the fauna to be a part 

 of that described by Dr. Leidy and Professor Cope as occurring in the 

 Pliocene deposits of Colorado and Dakota. 



In this species, the (supposed) first molar is described as having the 

 triturating surface twice as long as broad, with an entering loop of enamel on 

 the inner side ; the last molar as being as wide antero-posteriorly as trans- 

 versely, the shaft curved backward, the posterior column subcylindric, half 

 the diameter of the anterior. This species Professor Cope supposes to have 

 been of about the size of the Nortiiern Hare {Lcpus americanvs), and liciico 

 considcraldy larger than Palaolagus hmjdeni, which is described by Dr. Leidy 

 as being somewhat smaller than Z.e/)ai' s^/t^a/jca.*. 



Genus PRAOTIIERIUM Cope. '" 



Praolherium Copb, Proc. Atiicr. Pbil. Soc, xii, 1871, 93. 



" Molars similar to those of Lepus, rootless, with oval crowns transverse 

 to the axis of the scries, all simple ; masticatory surface not divided by median 



