14 Bulletin American Museum of Natural History. [Vol. XXXIV, 
specimens from the upper part of the Lower Wasatch. ‘The matrix of the 
type specimen of A. ursidens as well as those referred to this species by 
Osborn in 1892 indicate that they are also from the Lysite horizon. 
The new material shows that the lower jaw of Anacodon was heavily 
flanged at the chin as in the Macherodonts, the lower canine and incisors 
reduced and compressed even more than in Hoplophoneus. This probably 
indicates a large compressed sabre-like upper canine. 
The specimen from the Lysite indicates a larger but more primitive 
species than A. ursidens. The New Mexican specimen is smaller than any 
of those from Wyoming and is perhaps a more primitive mutant, but is 
referred to Cope’s species. 
The flanged lowér jaw is a quite unexpected character in this genus, for 
no trace of this specialization is present in Clenodon nor as far as I know in 
Arctocyon. It points evidently to some-highly specialized food-habits, but 
is not comparable with that of the Macherodonts nor with the Oxyzenid 
genus Macheroides, since it is here associated with frugivorous or omnivorous 
cheek teeth. Bathyopsis and Uintatherium are similarly flanged, but there 
is no close parallelism in the cheek teeth. 
Anacodon ursidens Cope 1882. 
Anacodon ursidens Corr 1882, Pal. Bull. No. 34, Proc. Am. Phil. Soc., Vol. XX, 
p. 182; 1885, Tertiary Vertebrata, p. 427, pl. xxve, fig. 2; OsBorn (& WoRTMAN), 
1892, Bull. Am. Mus. Nat. Hist., Vol. IV, p. 115, fig. 13. 
Type, No. 4261, parts of lower jaws from the Wasatch of the Big Horn Basin, 
Wyoming. 
Distinctive characters: m_3=38. P+ rounded, subquadrate, with low protocone 
and deuterocone and distinct tritto- and tetartocone. Molars with rounded outline, 
cones low, much obscured by surface rugosities. 
To this species is referred in addition to i specimens described by 
Osborn a lower jaw, No. 15711, from the top of the Gray Bull beds near 
Fenton in the Big Horn Basin. The greater part of the left ramus and about 
half of the right ramus are preserved. The j jaw deepens anteriorly, and 
shows a sharply marked, broad, thin and deep dependent flange; the an- 
terior part of the jaw is concave externally, the flange bordered anteriorly 
by a strong crest which runs up to the canine alveolus. The canine alveolus 
is relatively small and much compressed, the incisive alveoli are obscurely 
indicated but were evidently small, laterally compressed and crowded out 
of series. Behind the canine is a long diastema followed by the vestigial ps 
and small two-rooted pa. Mis much smaller than ms, m3 somewhat smaller. 
The jaw becomes shallower but much thicker under the posterior molars. 
