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UINTA SELENODONTS 



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as short splints, though the former alternative seems the more probable one. 

 Metatarsal iii. is long and quite stout, much shorter, however, than in Proty- 

 lopus and heavier than in Lcptorcodon. The proximal end is narrow, but is 

 given considerable dorso-plantar extension by the large projection from the 

 plantar side. On the tibial side of the head is a shallow groove for the 

 reception of mt. ii. From the size and shape of this groove it is evident that 

 the missing metatarsal was exceedingly small. On the fibular side is a round 

 pit which receives a projection from mt. iv. The shaft is long, stout, and 

 nearly straight ; it is broad transversely, but compressed antero-posteriorly, 

 except in the proximal portion, which is quite thick in the dorso-plantar 

 dimension ; in breadth the shaft increases gradually and uniformly towards 

 the distal end. The distal trochlea is demarcated from the shaft by a very 

 distinct pit ; the carina is but moderately developed and hardly at all visible 

 from the front. The shape of the trochlea shown in the drawing (Plate III., 

 fig. 1 8) is probably due to the crushing which the fossil has undergone. 



Metatarsal iv. differs but slightly from mt. iii., except that the shaft is a 

 little broader. The head is narrow and the shaft widens gradually to the 

 distal end ; the plantar projection is rather small, decidedly smaller than in 

 Protylopus, and the depression on the fibular side which receives mt. v. is even 

 shorter and shallower than the groove on mt. iii. for mt. ii. In Lcptomeryx 

 the median metatarsals have coalesced to form a cannon-bone, while the lateral 

 pair are reduced to short splints, which are also anchylosed with the cannon- 

 bone. 



MEASUREMENTS. 



Astragalus, length .... 



" width, proximal trochlea 



'* " distal trochlea . 



Calcaneum, length (est.) 



Cuboid, height .... 



width .... 



" thickness 



Metatarsal iii., width, proximal end 



" " distal end 



Metatarsal iv., length 



0.016 



Metatarsal iv., width, proximal enc 



0.0055 



.008 



" " distal end 



.00S5 



.008 



Phalanx 1, length . 



.018 



.031 



width, proximal end 



.006 



.0115 



" distal end . 



.0045 



.006 



Phalanx 2, length 



.01 1 



.01 1 



" width, proximal end 



.0055 



.0055 



" " distal end . 



.004 



.0065 



Ungual phalanx, length 



.0105 



.052 



width proximal enc 



.005 



The phalanges are very much like those of Protylopus, except that they 

 are relatively longer and more slender. As compared with the length of the 

 metatarsals, the proximal phalanx is very long and slender; its proximal 



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