FORT U2^'I0X OF CRAZY MOUNTAIN FIELD, MONT. 189 



CLAENODON VECORDENSIS Simpson 



Figure 42 



Claenodon vecordensis Simpson', 1935d, p. 232. 



Type.— U.S. 'NM. no. 13781, left AP-^. Collected by A. C. Silber- 

 ling and G. G. Simpson, 1932. 



Horizon and locality. — Loc. 9, 300 feet above the base of Fort Union 

 No. 1, Crazy Mountain Field, Mont. 



Diagnosis. — M^ similar to that of C. silberlingi in outline but 10-20 

 percent larger and somewhat more transverse; hypocone vestigial, 

 strong crenulated internal cingulum. M^ relatively as large as in 

 C.ferox and similar in structure except for smaller metacone and more 

 evenly rounded external border; vestigial hypocone present. 



Discussion. — This species is smaller than the smallest IvQown variants 

 of C. ferox, has a smaller hypocone on M^, and the contours of M^ 

 and M^ are different and beyond the known range of variation of that 

 species. C. silberlingi is somewhat smaller and has different tooth 

 proportions. M^ is much larger and less transverse than in C. mon- 

 tanensis and has the posterior part better developed. The small 

 unnamed Torre j on species is much smaller and has less wrinkled 

 enamel, and the internal cingulum is feebler or absent. 



FrGURE i2.— Claenodon 

 vecordensis Simpson, 

 U.S.N.M. DO. 13781, left 

 M2-3, crown view. Nat- 

 ural size. 



Figure i3.—'! Claenodon 



sp., U.S.N.M. no. 6158, 



left Ml, crown view. 



Natural size. 



It is unfortunate that another poorly known species must be added 

 to this genus, already burdened with several species of doubtful status, 

 but the present specimen is identifiable and surely cannot enter into 

 any species previously established so far as their range of variation is 

 known or can be fauiy inferred. It is, furthermore, from a very dif- 

 ferent geological horizon from the other Fort Union claenodonts and 

 one from which little material has been obtained, so that its strati- 

 graphic importance also necessitates some convenient designation for it. 



Measurements: Length M^, 9.0; width M^, 13.5; length M^, 6.7; 

 width M\ 10.0. 



7CLAENODON species 



Figure 43 



U.S.N.M. no. 6158, from the Gidley Quarry, is a left lower jaw frag- 

 ment with Ml. Among Dr. Gidley's notes are two sheets devoted to a 



