346 THE PUERCO FAUNA. 



Measurements. 



u. 



Length of last sis molars 075 



length of true molars 038 



Ixiigthof Pin. iv 012o 



Loiigth of M. ii..., 013:> 



Lcnttthof M. iii 0130 



Depth (if ramus at M. ii 029 



Northwestern New Mexico; D. Baldwin. 



SARCOTHRAUSTES Cope. 



Palcontological Bulletin, No. 34, p. 193, February 20th, 1882 ; Proceed. Am. Phil. Sec, 1881, p. 193. 



We have in evidence of the characters of this genus the last two 

 superior molars, the last one lacking the crown; and parts of both man- 

 diljular rami, which exhibit teeth as far posteriorly as the first true molar 

 inclusive; all belonging to one individual. A part of a skeleton of a 

 second individual, which includes a fragment of lower jaw, belongs prob- 

 ably to this species. 



Sarcothraustes resembles both Amhlydonus and Mesonyx, but it is prob- 

 ably to the latter genus that it is allied. The last superior molar is trans- 

 verse, much as in Oxycena. Tlie crown of the penultimate is subtriangular 

 and transverse. It has two external subconic cusps and a single internal 

 lobe, whose section on wearing is a V, each branch of the face extending 

 to the base of the corresponding external tubercle. There are three small 

 inferior incisors, and a large canine. There are probably only three inferior 

 premolars, the first one rooted. The crown of the second has no heel 

 The crown of the third has a short wide heel. The crown of the first true 

 molar consists of an anterior elevated cone and a posterior heel. The 

 latter is wide, having a posterior transverse, as well as a longitudinal median 

 keel. The fragments of the supposed second individual include two large 

 glenoid cavities with strong preglenoid crests, as in Mesonyx. 



As compared with Mesonyx, this genus differs in the V-shaped crest of 

 the penultimate superior molar; in Mesonyx it is represented by a simple 

 cone. The last superior molar of Mesonyx is triangular and not transverse, 

 but the composition of the crown of that tooth in Sarcothramtes must bo 

 known before the value of this character can be ascertained. If the view 

 that Sarcothraustes has but three inferior premolars be correct, this character 

 distinguishes it from Mesonyx, as do also the transversely expanded heels 

 of the molars. 



