1902.] Matthew^ A Horned Rodent from Colorado Miocene. 3^9 



type, upper and lower jaws and fragments of skeleton from 

 same level and region. 



This skull is much more depressed on the basicranial axis 

 than P . agapetillus ; it has a long and heavy muzzle, unlike 

 the slender, sharp muzzles of the two preceding species; the 

 teeth are larger than 

 those of P. Jiaydeni, 

 but resemble them in 

 pattern; the length 

 of the diastema is 

 equal to that in P. 

 turgidus, but the 

 teeth are much 

 smaller, and of more 



_ Fig. 17. Paleeolagus intermedins. Skull, natural size. 



LepliS-\\k.Q pattern ; Type. No. 8722. white River (Martin Canon Beds), Colorado 



the skeleton appears 



to be as large as that of P . turgidus, and of similar propor- 

 tions. The postfrontal process is nearly as large as in Lepus 

 ennisiauiis; the muzzle is of the same length as in that species, 

 but heavier; the basifacial axis is somewhat less depressed, 

 and the brain-case is distinctlv smaller. 



p2 3 4 m I 2 3 



Palaeolagus turgidus Cope. 

 P. triplex Cope; ? Tricium paniense Cope. 



Young jaws of this species show a third lobe on the p^-nig 

 and a third lobe on P3, both of which disappear in the old ani- 

 mal. The jaw on which P. triplex was founded appears to be 

 a juvenile stage of P. turgidus, in which these characters are 

 very marked. We have no other jaws of the same age; but 

 if the twelve or fourteen examples of lower jaws be arranged 

 according to age (determined by wear on end of P3) they form 

 a perfect series from P. triplex to the type of P. turgidus. 

 Cope, in comparing the series, came to the conclusion that 

 the difference between P. turgidus and P. triplex could not 

 be entirely explained as a matter of age; but the present 

 writer is unable to see sufficient difference to warrant the 

 retention of the species. 



