A NEW HORNED RODENT FROM T?IE MIOCENE OF 



KANSAS. 



By Jamks Williams Gidley, 



Of ilw Depart me III of (lenlogn. United Slates Nalioiial Mnneum. 



In 1902 '' Dr. W. D. Matthew described a new and most interesting 

 Mylag-aulid rodent, Ceratogaulus rTiinocei'us^ from the middle Miocene 

 beds at Pawnee Buttes, Colorado. The genus is especially distinguished 

 by a pair of w^ell developed horncore-like processes situated on the nasal 

 bones, a most unexpected and unique character for a rodent and 

 entirely unknown prior to Matthew's discovery. 



While recently unpacking some boxes of Miocene fossils, which for 

 a number of j^ears have been stored away in the United States National 

 Museum, a second specimen was found, representing a new but 

 closely related genus in which nasal horns are even more prominently 

 developed than in Ceratogaulus. This specimen, a nearly complete 

 skeleton, was originally obtained by the late Mr. John Bell Hatcher, 

 while collecting fossils for Prof. O. C. Marsh under the auspices of 

 the United States Geological Surve}', in 1885. It comes from the 

 upper Miocene beds near Long Island, Kansas. Although obtained 

 so long ago, the specimen when found had apparentl}" not been 

 unpacked since arriving from the tield and was probably never 

 examined ])y Marsh. 



With this more complete material it is now possible to contirm some 

 of Matthew's conclusions regarding the association of the material 

 described by him, to determine more detinitely the affinities of the 

 famil}' M} lagaulidie, and to give a more complete knowledge of the 

 osteological characters of this little known hut interesting group of 

 rodents. 



1 have been greatly aided in the preparation of this paper b}^ having 

 for comparison all the Mylagaulid material in the American Museum 

 of Natural History collection, whieh was generously placed at my dis- 

 posal through the kindness of Prof. Henry F. Osborn and Dr. W. D. 

 Matthew. 



"Bull. Amer. Mus. Nat. Hist., XVI, 1902, p. 29L 



Proceedings U. S. National Museum, Vol. XXXII— No. 1554. 



627 



