the Marsh Collection. 399 



is more discrepancy, as the first molar and premolars are 

 relatively markedly smaller, as compared with molars 

 2 and 3^f the upper series, thus indicating a greater 

 degree of evolutionary advance. 



3Ieasiirements. 



mm.. 



Length. P, to M3 78.5 



Diastema, C to P^ 16.0 



Diastema, PMo P- 20.0 



P*, ant-post, diameter 11.0 



P*, transverse diameter 10.0 



M^, ant.-post. diameter 13.0 



M^, ant.-post. diameter 17.3 



IVP, transverse diameter 16.5 



M^ ant.-post. diameter 20.0 



M^, transverse diameter 17.4 



The proximal third of a left metatarsal is associated 

 with the jaw and is coossified by the plantar (palmar of 

 Peterson) processes. It corresponds in every way with 

 the jaw, but may not pertain to the same individual, 

 as the same lot contained non-camel material as well. 

 The component elements are very closely applied, so 

 much so that were it not for a film of matrix between 

 their approximated surfaces, they would appear to be 

 coossified throughout. This very close approximation, 

 together with the final fusion of the plantar processes,^ 

 is probably due to the age of the individual. It is in 

 agreement with Oxydactylus (see below). 



Measurements of cannon-hone. 



mm. 



Proximal width 25.9 



Ant.-post. diameter over plantar processes 24.4 



Width of shaft, 50 mm. below summit 15.6 



Specimen No. 10922, Y. P. M., consists of a right man- 

 dible, the teeth of which show fair correspondence with 

 those of the upper jaw. One abnormal peculiarity, how- 

 ever, is a supernumerary P^, the presence of which pre- 

 vents an accurate fit with an upper jaw. No. 10917, as the 

 smaller forward tooth interferes with P\ Both first 

 lower premolars are double-rooted, with trenchant 



2 In the tjpe of Paratylopus sternbergi (Cope) in the American Museum 

 the plantar processes are entirely separated throughout. 



