1895.] NATURAL SCIENCES OF PHILADELPHIA. 245 



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second upper molar of a bison found at Pittston, Luzerne Co., Penn- 

 sylvania, in association with the remains of the mastodon and fossil 

 horse. This he identified as belonging to the extinct Bison latifrons. 

 Dr. Allien 1 contends that this tooth not only lacks the accessory 

 column characteristic of the genus Bison but "it is in any case too 

 small for a tooth of Bison latifrons," and thinks it "undoubtedly 

 referable to the extinct musk-ox." Having examined the speci- 

 men in question and compared it with corresponding teeth of 

 Bison-bison and the types of extinct muskox in the museum of the 

 Academy of Natural Sciences of Philadelphia I find that this 

 Pittston specimen is very much worn, the triturating surface hav- 

 ing reached to the alveolar base of the enamel on the anterior and pos- 

 terior sides. The roots of the tooth are intact, and comparison with 

 a corresponding molar removed from the jaw of an adult Bison bison 

 from Utah shows that the Pittston specimen is not materially larger 

 than the one from Utah. Owing to the wearing of these molar 

 teeth their triturating surface changes from an oblong, twice as long 

 as wide, to a nearly square figure of nearly twice the triturating area 

 seen in the teeth of a younger adult animal of same size. Dr. Leidy's 

 oversight of this fact was probably the reason for his identification of 

 the tooth as that of Bison latifrons, to which species, it may be re- 

 marked, he had referred larger specimens of the smaller B. antiquus. 



In this respect Dr. Allen's position is sound; the tooth is too small 

 to belong to latifrons. 



( )n the other hand it is impossible that the tooth belongs to the ex- 

 tinct musk-ox, the corresponding molar in that animal being nearly 

 twice as large in the type specimens preserved in the Museum of the 

 Academy. The accessory cusp of the molars of Ovibos cavifrons is 

 even more prominent than in Bison, so that the lack of this cusp in 

 the Pittston specimen as effectually removes it from one genus as from 

 the other, and I am inclined to consider the oval median islet in the 

 specimen as representing an abnormal displacement of the accessory 

 cusp of the genus Bison. If this is granted the other characters in- 

 dicate it to belong to Bison bison. 



Of interest in this connection are the Hist and third lower molars 

 of an adult bison, evidently from the same individual, which were 

 found in the collection of the Academy. These are mounted together 



The American Bisons, p. 1:2. 



