84 CONTRIBUTIONS FROM WALKER MUSEUM 
position in the carpus and is much larger than the second. Centrale 
2 lies between the ulnare and the third, fourth, and fifth carpals, but 
is surrounded by bones, as its outer side articulates with the sesamoid. 
The form and articulation of the five carpals of the distal row are best 
Fic. 1.—Lower side of the manus of the right foot of Dimetrodon sp. r’, radiale; 
u’, ulnare; 7, intermedium; ¢ 1, centrale one; ¢ 2, centrale two; s, sesamoid; 1, 2, 3, 4, 5, 
carpals and metacarpals. Natural size. 
seen from the figure. The fifth carpal is peculiar in its prominent 
position at the side of the carpus, standing well away from the rest of 
the bones. 
A second specimen of Dimetrodon discovered the same summer 
afforded a nearly complete anterior portion of the skeleton. It has 
received the number toot in the Chicago collection. The bones of 
— Ta 
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