Cope. | 444 [May 19, 



that the additional facet of the astragalus is produced. Its relations will 

 therefore be considered rather than those of the astragalus in framing the 

 following definitions : 



Order I. Scaphoides supported by trapezoides and not by magnum, 

 which supports lunar. Cuboid articulating proximally with calcaneum 

 only Taxeopoda. 



Order II. Scaphoides supported by trapezoides, and not by magnum, 

 which supports lunar. Cuboid extended inwards and articulating with 

 the distal face of the navicular Proboscidea. 



Order III. Scaphoides supported by trapezoides and not by magnum, 

 which Atith unciform, supports the lunar. Cuboid extended inwards and 

 articulating with astragalus. Amblypoda. 



Order IV. Scaphoides supported by magnum, which with the unciform 

 also supports the lunar. Cuboid extended inwards so as to articulate with 

 the astragalus .-> Diplarthra. 



The sub-orders are defined as follows : 



I. TAXEOPODA. 



There are two, perhaps three sub-orders of the Taxeopoda; the Hyracoidea, 

 the Oondylarthra, and perhaps the Toxodontia.- The Toxodontia are how- 

 ever not sufficiently known for final reference^ The sub-orders are de- 

 fined as follows : 



A postglenoid process ; no fibular facet of calcaneum, but an interlocking 

 articulation between fibula and astragalus ; ungual phalanges trun- 

 cate Hyracoidea. 



A postglenoid process ; no fibular facets on either calcaneum or astragalus ; 



a third trochanter of the femur ; lingual phalanges acuminate 



Oondylarthra. 

 There are a good many other subordinate characters which distinguish 

 the Condylarthra, which will be given in my forthcoming volume iv of 

 the Hayden Survey, on the Tertiary Vertebrata of "Western America. 



II. PROBOSCIDEA. 



There may be two sub -orders of this order, the Proboscidea and the 

 Toxodontia. I do not know the Carpus of Toxodon, but if it does not differ 

 more from that of the elephants than the tarsus does ; it is not entitled 

 to subordinal distinction from the Proboscidea. The sub-order of Pro- 

 boscidea is defined as follows : 



A fibular articulation of the calcaneum ; no postglenoid process ; no third 

 trochanter of femur Proboscidea . 



* See my remarks on Toxodon, Proceedings Ainer. Philosoph. Society, 1881, 

 p. 402. 



t The considerable resemblance between the dentition of Toxodon and Hprax 

 must not be overlooked. 



