R. S. Lull — Primitive Pecora in Yale Museum. Ill 



Art. IX. — Primitive Pecora in the Yale Museum; by 

 Richard S. Lull. 



[Contributions from the Othniel Charles Marsh Publication Fund, Peabody 

 Museum, Yale University, New Haven, Conn.] 



The genus Hypertragulus was established in 1873 by 

 Professor Cope to include a group of deer-like creatures 

 which in some respects resembled those of the genus 

 Lept ornery x very closely. The main distinctions as 

 shown by the dentition are as follows : 



Hypertragulus possesses : the superior laniary canine, 

 P 1 , separated from both C 1 and P 2 by diastemata, upper 

 molars without mesostyle, and M 3 bearing three ribs on 

 its outer face, all of which are the converse of Lepto- 

 meryx. The lower dentition differs from that of Lepto- 

 meryx in the development of a caniniform P x , a diastema 

 behind P 2 , a compressed and elevated P 3 which is shorter 

 than the three-lobed P 4 , and in the fact that in M 3 the 

 posterior crescents are opposite each other, subequal in 

 size, and not separated posteriorly by a fissure. 



The geological range of Hypertragulus is apparently 

 from Middle Oligocene Oreoclon beds to Lower Miocene 

 Rosebud. Geographically, the genus is found in the 

 Great Plains region — Colorado to South Dakota, Mon- 

 tana, Canada, and the John Day Basin of Oregon. 



The following species have been named, H. calcaratus 

 Cope from the Great Plains region being the type of the 



H. calcaratus Cope 1873. 



H. tricostatus Cope 1873. 



H. transversus Cope 1889. 



H. hesperius Hay 1902. 



H. ordinatus Matthew 1907. 



Allomeryx planiceps Sinclair 1905. 



To which are added in this paper : 



H. minutus, sp. nov. 

 Leptomeryx obliquidens, sp. nov. 

 Xanotragulus loomisi, gen. et sp. nov. 



Am. Jour. Sci.— Fifth Series, Vol. IV, No. 20.— August, 1922. 



