TILLODONTIA. 



Esthonyx Cope, Lower and Middle Eocene (Wasatch and Bridger), Anchip- 

 podus Leidy, Bridger Eocene ; Tillotherium Marsh, Bridgor Eocene, the 

 most specialised with dentition i'i c } p% m f, incisors very rodent-like, 

 but lower jaw with transverse condyle. 



Here may be mentioned the Taeniodonta Cope (Stylinodonta Marsh) 

 lately^renamed Ganodonta,* known by fragmentary remains. The dental 

 series' is continuous or nearly so ; there is a tendency to reduction of 

 incisors, and the canines are large and sometimes resemble rodent incisors ; 

 the grinders are bilophodont or quadrituberculate (or tritubercular) and 



there appears to 



, -,, ^ . be a deficiency 



" if - A CA vi of enamel ; in 



some species 

 there is hypso- 

 dontyand growth 

 from persistent 

 pulps; the radius 

 and ulna appear 

 to have admitted 

 of pronation and 

 supinationof the 

 manus, a clavicle 

 is present, and 

 the digits had 

 curved claws ; 

 there was a weak 

 third trochanter. 

 A fragmentary 

 manus seems to 

 resemble that of 

 a ground -sloth, 

 and on this evid- 

 ence together 

 with the poverty 

 of enamel in the 

 molars and cer- 

 tain features of 

 the pelvis and 

 vertebrae has 

 been evolved the 

 certainty that 

 these animals are 

 the Eocene fore- 

 runners of the Edentata. All are from the Lower Eocene (Puerco, 

 Wasatch and Bridger Beds) of N. America. Hemiganus Cope, Puerco 

 Beds. Psittacoiherium Cope, Upper Puerco, this is the genus of which the 

 ground sloth-like manus is known, canines and grinders rooted. Gala- 

 modon Cope, Wasatch Beds, and Eocene of England, with large rootless 

 canines like a rodent incisor, grinders with roots. Stylinodon Marsh, 

 Wind River, and Bridger Eocene, canines and all lower teeth rootless. It 

 is quite possible that the Ganodonta are allied to the Edentata, but there 



FIG. 320,j Homalodont other ium segoviae, A right manus, B third digit 

 in side view, x | (after Ameghino, from Woodward), en cunei- 

 form, In lunar, m magnum, me metacarpal, p pisiform, sc scaphoid, 

 id trapezoid, tm trapezum, un unciform, i-v digits, 1-3 phalanges. 



* Wortman, op. cit. 



