AMBLYPODA. 507 



M. 



„. , „ ...(vertical. 0045 



Diameters Pm. m ^ 



' auteioposterior 0U4 



Wiiltli of inferior face of symphysis 008 



Depth of ramus at Pm. lit 009 



Depth of ramus at M. iii t'103 



This species was obtained by Mr. D. Baldwin from beds of probably 

 lowest Wasatch age, in New Mexico. 



AMBLYPODA. 



Cope System. Cat. Vert. Eoceue New Mexico, U. S. Geog. Siirvs. W. of lOOtliM., 1875, 



p. 28. Keport do. iv, pt. ii, p. 170. 



Mammalia Avith small (! smooth) cerebral hemispheres, which leave the 

 olfactory lobes and the cerebellum exposed. The feet short and planti- 

 grade, with numei'ous (in the known genera five) digits, terminating in flat 

 hoof-bearing ungual plialanges. The seven bones of the carpus distinct; 

 the unciform articulating with the lunar as well as with the cuneiform. 

 The astragalus flat, Avithout trochlear groove, and attached to the tibia with 

 little freedom of movement; its distal extremity divided into two facets, 

 one for the navicular, and more or less of the other for the cuboid bone. 

 Molars invested with enamel, with wide ci'OAvns and crests. A post-glenoid 

 process. 



The above characteristics are the only ones which can, in the author's 

 estimation, be admitted into the ordinal categorA , for although the animals 

 embraced in the Amblypoda present many other pecitliarities, tliey are sitch 

 as may readily vary within the limits of an order, and in fact do so in the 

 families of many of the orders known to us. The above definition displays 

 a double set of afiinities, viz: those indicated by the structure of the feet, 

 and those expressed by the type of the brain. The former exhibit a 

 close resemblance to the feet of the Prohoscidea, the approach being 

 greatest in the hind foot. The principal difference in this extremity, is seen 

 in the extension of the navicular articulation over the entire distal end of 

 the astragalus in the Prohoscidea, Avhile in the Amhhjpoda, the navicular is 

 shortened, tlius permitting the cvxboid to come in contact with the external 

 part of the distal extremity of the astragalus. The I'ulfoid v.^ alike in the 

 two orders, having considerable transverse extent, and suppovting the 



