188 THE WASATCH AND lUUDUKU FAUN-E. 



liaritieR. Chief amonfr these is the character of tlie inferior canines. Tn the 

 TiUoihnta tliey are either wanting, as in Erinacetts, according to the Cu\'i- 

 erian diagnosis, or they are insignificant. In Cahniodon they are of lai-ge 

 size, and tliough not as long-rooted as the second incisors, grow from jier- 

 sistent pulps. They have two enamel faces, the anterior and posterior, the 

 former like the corresponding face of the rodent incisors. The function of 

 the ailult crown is that of a grinding tooth. This character distinguislies 

 Cahutiodon as a form as different from Tillotherium as the latter is from 

 Esthonyx. There are, however, other characters. The external incisors, 

 wanting in Tillolhcriiim, are here largely developed, and though not growing 

 from persistent pulps, have but one, an external band-like enamel face. 

 TIrIt function is also that of grinders The fact that the rodent teeth in the 

 lower jaw are the second incisors, renders it probable that those of the Tillo- 

 donta hold the same position in the jaw. This is to be anticipated from the 

 arrangement in Enthoni/x, where the second inferior incisors are much larger 

 than the first and third. The superior dentition of the Taniodonta is unknown. 



Two families represented this suborder in the Eocene period of North 

 America. The first or Ectoganid<z, with two species, possess molar teeth 

 with several roots. In the Calamodontidcp, with five species, each lower molar 

 has a simple conic fang. The great reduction in the extent of the enamel 

 investment is an interesting approximation to the Edentata, where this sub- 

 stance is altogether wanting. The reduction is greatest on the adjacent sides 

 of the molars; it has a little greater extent on the inner side, while it extends as 

 a band on the exterior side, so that in worn teeth this surface alone remains. 

 In addition, there are a heavy cementum investiture and undivided roots in 

 the genus Calamodon, features essentially characteristic of the Edentata. 



Thus we have in the Tceniodonta the first hint as to the relations of the 

 Edentata in early Tertiary time. 



CALAMODON Cope. 



Eeiiort Vert. F088. New Mexico, U. S. Geog. Surv«. W. of 100th M., 1874, p. 5; Id.. Ann. Report U. S. 

 Geol. SiirvB. W. of UKltli M., Iii74, p. 117; System. Cat. Vert. Koiene N.-w M<-xico, U. S. Geog. 

 SurvB. W. of 100th M., le7o, ji. 24 ; Keport U. S. Cicog. Survs. W. of lOotli M., vol. iv, pt. ii, 1S77, 

 p. 162. 



Fornnila of inferior dentition, I. 8; C. 1, M. 5; without distinction into 

 premolars and molars. First incisors small, with conic roots; second inci- 



