608 



TILLODONTIA. 



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

 podus Leidy, Bridger Eocene ; Tillotherium Marsh, Bridgcn- Eocene, the 

 niost speciaUsed with dentition i ^ c -\- p § m -;J, incisors very rodent-Uke, 

 but lower jaw with transverse condyle. 



Here may be mentioned the Taeniodonta Cope {Stylinodonta INIarsh) 

 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 ai'e large and sometimes resemble rodent incisors ; 

 tlie grinders are bilophodont or c(uadrituberculate (or tritubercular) and 



there appears to 

 be a deficiency 

 of enamel ; in 

 some species 

 there is hypso 

 dontyand growth 

 from persistent 

 pulps; the radius 

 and ulna appear 

 to have admitted 

 of pronation and 

 supination of 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 

 beenevolNcdlhe 

 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. Hetniganus Cope, Puerco 

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

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

 rnodon 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. 320i — Homalodontotherium segoviae, A right maims, B third digit 

 ill sido view, x = (after Amegliino, from Woodward), en cunei- 

 form, in lunar, m magnum, mc metacarpal, p pisiform, sc scaphoid, 

 id trapezoid, im trapezum, iin unciform, i-v digits, 1-3 phalanges. 



* Wortman, op. cit. 



