JSSI.] XJI [Cope. 



Deltatherium, Oxycena ; Manteodon, Ectacodon, Metalophodon ; Anacodon, 

 Oligotomus, Systemodon ; Mioclcenus. Three of these genera have been 

 found in the Bridger, and five have been obtained in the lower Eocene of 

 New Mexico. Five of the genera are new to science. 



An especial feature of the Big-Horn collection, as distinguishing it from 

 those brought from other regions of the "Wasatch formation, is the presence 

 of numerous species of Phenacodus, and of new and rare species and 

 genera of Coryphodontidce. 



II. The Fauna of the Catathl^eus Beds ok Lowest Eocene op 

 New Mexico. 



A number of new species and genera from this horizon were described 

 in my Paleontological Bulletin No. 33. The present paper adds a few to 

 this list. Up to the present time no species of Coryphodon, and but few 

 specimens of Hyracotherium have been discovered in this formation, thus 

 exhibiting a marked contrast to the "Wasatch beds. The predominant 

 genus is Catathlmus, which is represented by one very abundant species. 

 The genera of Creodonta are mostly distinct from those of the Wasatch. 

 The Diplarthrous Perissodactyla, so numerous in the Wasatch, are rare 

 here. The genus which is well represented in both formations, is Phena- 

 codus; and Mioclmim occurs in both. Mesodonta are much less numerous 

 than in the Wasatch, and Amblypoda have not yet certainly been found. 



This is the only Tertiary formation where the Laramie genus Champso- 

 saurus occurs. It is represented by three species. 



PSITTACOTHEKITJM MTJIiTIFRAGTJM Cope. 



American Naturalist, 1882, p. 156, Jan. 25th. 



An interesting new form of this sub-order has been found in the Gatath- 

 Imus beds (probably the Puerco formation) of New Mexico. It differs 

 widely from the two genera hitherto known, Anchvppodus and Tillothe- 

 rium. Owing to the absence of the superior dental series, it is not possible 

 to be sure which is the canine. The inferior dental formula may be there- 

 fore written, I. 2 ; C. 1 ; P-m. 3 ; M. 3 ; or I. 3 ; C. ; P-m. 3 ; M. 3 ; or 

 I. 3 ; C. 1 ; P-m. 2 ; M. 3. The first and second incisors are large and 

 rodent-like, growing from persistent pulps ; the second are the larger. 

 The third, or canines, are small and probably not gliriform. There is 

 no diastema. The first premolar (or canine) has a compressed crown 

 with two cusps placed transversely to the jaw axis, and has a complete 

 enamel sheath, and probably two roots. The succeeding tooth is also 

 transverse, and is two-rooted, judging from the alveolus. The first and 

 second true molars are rooted, and the crown consists of two transverse 

 separated crests, each partially divided into two tubercles. On wearing, 

 the grinding surface of each assumes the form of a letter B with the con- 

 vexities anterior. The last inferior molar is injured. The rami are short, 

 and the symphysis deep and recurved. 



Specific characters. The base of the coronoid process is opposite the 

 junction of the second and third true molars. The ramus is deep and mod- 



