CEEODONTA. 273 



From the lower Puerco Eocene beds of New Mexico, near the Canyon 

 Largo, a branch of the great canyon of the San Juan Eiver. 



Triisodon heilpkinianus Cope. 



Proceedings American Philosophical Society, 1881, p. 193. Paleontological Bulletin, No. 34, p. 193, Feb. 



20th, 1862. 

 Plate XXVIII a; fig. 2. 



This species may be readily recognized as smaller than the T. quivi- 

 rensis, and as having the anterior inner cusp of the inferior true molar of 

 larger proportions than in the corresponding teeth of the latter species. It 

 is only represented in my collection by a portion of a lower jaw, which 

 supports only one well-preserved molar. As the fourth premolar is not 

 present, it is not positively ascertained that the species does not belong to 

 Idops. 



The anterior cusp is very low, and is nearer the inside than the middle 

 of the anterior border. The principal anterior cusps are opposite, and the 

 external is a little the larger. The heel is larger than the basis of the an- 

 terior cusps, and has convex borders. Its internal border supports three 

 tubercles, and the external border rises into a cutting lobe with lenticular 

 section. Enamel smooth. No cingula, but the external base is injured. 



Measurements. 



M. 



. , (of cusps 0070 



p-ert.cal|^f^^^j O^.g 



Biameters of inferior molar ; I anteroposterior 0110 



V transverse 0i.'65 



Puerco beds of New Mexico. 



Dedicated to my friend, Professor Angelo Heilprin, of Philadelphia, 



who has contributed to our knowledge of the fauna and geology of the 



Eocene period. 



Triisodon levisanus Cope. 



Proceedings American Philosophical Society, 1883, p. 446. 

 Plate XXIV f ; fig. 3. 



This creodont is represented by a part of a right mandibular ramus, 



which contains the fourth premolar minus its principal cusp, and the first 



and second true molars, with the alveoli of the third. The ramus is deep, 



and probably belonged to an animal of about the size of the red fox. The 

 18 c 



