352 Annals of the Carnegie Museum. 



Not only is the skeleton of T. dispar smaller and somewhat less 

 robust than that of T. rohitstum, but there are still other differences 

 which appear even upon the most superficial examination. Compare 

 the broad heavy neural S])ine of the first dorsal of the American 

 Museum skeleton of T. rohiistum with the slender, pointed spine of 

 the same vertebra in our skeleton of T. dispar, which latter more 

 closely resembles that of the last cervical in the former than its homo- 

 logue, though really somewhat intermediate between the two. 



In the carpus of T. dispar the trapezium is present, though appar- 

 ently absent in T. robust iini and the other associated species from the 

 upper beds. The presence of this element in the carpus of the titano- 

 theres was first pointed out by Hatcher, who had detected it in some 

 feet found near the base of the beds in the Hat Creek basin in Nebraska, 

 while collecting for the late Professor Marsh in iS86. These feet 

 were not found associated with skulls, and at the time of publishing 

 my original notice (^See the Titanotheriiini Beds, by J. B. Hatcher, Am. 

 Nat., March, 1893) I correlated the presence of a trapezium with 

 those skulls described by Professor Marsh as possessing three lower 

 incisors and distinguished as Teleodus avus Marsh. Since then, how- 

 ever, I have discovered a number of other complete front feet and 

 examined many isolated trapezoids of the Titanotheres from the 

 lowermost horizon, and find that the trapezium is in every instance 

 present, as indicated either by the bone itself or its articular facet on 

 the surface of the trapezoid. It cannot therefore be considered as 

 belonging exclusively to those forms with three lower incisors, as I 

 had doubtfully suggested in my first paper. It is present on both the 

 front feet of our skeleton of T. dispar. 



Compared with the fore limbs the hind limbs are long and slender, 

 as is the case in all the Titanotheres, though the great expanse of the 

 ilia indicate rather robust proportions for the posterior region. 



The vertebral formula in our skeleton is C.7, D.17, L.3, S.4, C.18. 

 The third caudal carries a large chevron, as does also the same ver- 

 tebra in Professor Marsh's type of T. robiistiim. In the mounted 

 skeleton of the American Museum collections the tail of which is 

 composed of isolated vertebrte from different individuals, this ver- 

 tebra has been erroneously assigned the second position in the caudal 

 series. While as stated above the second caudal was not recovered in 

 our skeleton, nevertheless it is apparent that there is a vertebra miss- 

 ing between the first caudal and that bearing a chevron, and moreover 



