Art 1 



nsro. 6. 



NOTICES OF NEW VERTEBRATA FROM THE UPPER WATERS 

 OF BITTER CREEK, WYOMING TERRITORY. 



By Edward D. Cope. 



Synoplotheritjm lanius. Cope. Gen. et sp. nov. 



This genus possesses the dental formula so far as known, I. f c. JMj. In 

 the only specimen with molars, the crowns are much worn, but in all 

 the antero-posterior much exceeds the transverse diameter, and consisted 

 of two lobes. The posterior molar had no more lobes, and is smaller 

 than the penultimate. The first is two rooted, and is separated by a wide 

 space from the inferior canine. The superior canine is of disproportion- 

 ately large size, and issues a little behind the premaxillary suture. The 

 incisions are crowded closely together, and are of conic form. The ex- 

 terior is several times as large as the others. The inferior incisors are of 

 huge size, project upwards after the manner of rodents, and are inserted 

 by a short base into the solid symphysis. They are separated by a short 

 interspace, which is without alveoli. 



The fore foot possesses four digits, of which the inner is considerably 

 the shorter. *Phalanges not slender ; ungueals fiat, deeply fissured above. 

 Caudal vertebrae slender. 



This most remarkable genus is not at present referable to its proper 

 order. The superior anterior teeth are of carniverous type ; the opposing 

 teeth look like those of rodents, while the molar teeth differ from both. 

 It is allied to AncMppodus, Leidy, which is only known from mandibles. 

 This form Dr. Leidy has called the ' ' gnawing hog, ' ' but, as it probably 

 exhibits a structure similar to that seen in the present genus, it is obvi- 

 ous that the huge symphyseal teeth were not designed for gnawing in 

 the usual sense. I suspect these animals have lived largely on turtles,* ' 

 and that the structure in question was adapted for crushing their shells. 

 This is the more likely from the prodigious number of turtles which must 

 have existed contemporaneously with them. There are twenty species 

 described from the Bridger formation, and their numbers are legion, as 

 already described by Professor Marsh. Their bones are always in sight, 

 and six or eight are not unfrequently found lying together. 



Char, specif. The mandibular rami, posterior to the symphysis, are not 

 heavily constructed. The symphyseal teeth are very stout, and exhibit 

 two longitudinal grooves on the outer and outer inferior face ; the shaft is 

 compressed, and the worn surface is on the outer side, as produced by 

 the canines, and on the extremity, produced by the outer incisor. The 

 superior canine is compressed, and as large as that of a grizzly 

 bear. The outer incisor is nearly straight, and with conic crown. A 

 large part of its shaft is exposed at the bottom of a wide vertical 

 groove, which extends upwards between the canine tooth and a ridge de- 

 scending from the edge of the nares. The external nareal opening is en- 



*This view was already expressed in The Friend, Philada. , 1872, Winter. 



