194 THE WASATCH A^'D BIUDGER FAUN^. 



tance. The inner face of the tooth disphxys five facet-like bands of the 

 dentinal surface which soon disappear inferiorly. 



Measurements. 



it 



LfDKtli of tooth (root restored) 05t; 



Lt-ngtli (if eiiauiel baml .031 



Width of eaninel band at middle 0095 



DUmeters of middle of tooth ^''"'*^'"°P°«t«"°'" "130 



c transverse 009 



Long diameter of appx of tooth 008 



This tooth indicates a new and interesting type, perhaps, of Calamodon- 

 tidce, and one of which moi'e information will be awaited with interest. 

 Judging from the size of the tooth its possessor was as large as a sheep. 

 From the Puerco Eocene of New Mexico; from D. Baldwin. 



TILLODONTA. 



There are three allied groups represented by the genera EstJionyx, Til- 

 lotherinm, and Calamodon of the American Eocenes, which are equally unlike 

 each other. Esthonyx, as I long since showed, is related to the existing 

 Erinaceus; very nearly, indeed, if the dentition alone be considered. Its 

 anterior incisor teeth are usually developed and have, as in Erinaceus, long 

 roots. One pair at least in the lower jaw has enamel on the external face 

 only, and enjoys a considerable period of growth. The genus Tillothermm 

 is (tide Marsh) quite near to Esthonyx. Its molars and premolars are iden- 

 tical in character with those of that genus, the only important difference 

 being found in the incisors. Here, one pair above and one pair below are 

 faced with enamel in front only, and grow from persistent pulps as in the 

 Rodentia. This character has been included by Marsh in those he ascribes 

 to his "order" of Tillodontia, but as he includes Esthonyx in that order,* which 

 does not possess the charactei-, it is not very clear on what the supposed 

 order reposes. The rodent character of the incisors is the only one I know 

 of which distinguishes Tillotherium from the Insectivora. I have on this 

 account retained the Tillodonta as a suborder, and referred Esthonyx to the 

 Insectivora. 



There are three genera of this suborder: Psittacotherinm Cope, Anchij)- 

 podus Leidy, and Tillotherium Marsh. The last one I only know from the 



* Report of U. 8. Geol. Stirv. 40t.h parallel, by Clarence King, vol. i, page 377. 



