VERTEBRATE REMAINS, PORT KENNEDY BONE DEPOSIT. 213 



Variations in the forms of the canine molars are frequent. In some superior 

 teeth the posterior border is more pinched by the concavity than is normal ; and in 

 some the internal bulge is more prominent. In the latter case, there is a trace of 

 the anterior groove. Such teeth resemble nearly those of M. jeffersonii, but they 

 are always of consiberably smaller size, and the bulge is usually more anterior. 

 Inferior canine molars differ in the distinctness of the shallow concavities on each 

 side of the bulge, but the latter are rarely as distinct as in M. jeffersonii (" dis- 

 similis"), and the teeth are always smaller. The inferior canine molar is less curved 

 than the superior; in fact it is scarcely curved at all. 



The transverse section of the superior molars is triangular with obtuse apical 

 angle directed outward, excejDt in the case of the fourth, where the angle is directed 

 inward. The external angle of the first molar is more truncated than those of the 

 other molars. The posterior side of all the superior molars is slightly concave ; the 

 anterior slightly convex. The form of the last superior molar varies in different 

 individuals. Thus, in the specimen above described, the section of the only one 

 visible is triangular. In the second specimen mentioned, it is triangular on one 

 side and sub-triangular ovate on the other. In the third, the single one visible is 

 triangular, with a very obtuse apex. In the fourth, or nearly complete skull, it is 

 not triangular but is ovate, flattened posteriorly. In the skull of M. jeffersonii 

 from Natchez, described by Leidy, it is not as triangular as in the specimen of the 

 M. wheat ley i here first described, but is very much rounded at the apex. These 

 specimens show that Leidy' s species, M. dissimilis, must be regarded as founded on 

 an individual of M. jeffersonii, as already remarked. The only character by which 

 the superior molars of M. wheatleyi may be distinguished from those of M. jeffer- 

 sonii is their inferior size. 



The crowns of the inferior molars of the M. wheatleyi specimens above described 

 are not well displayed, so 1 refer to No. 2, where they can be seen. The grinding 

 faces are triangular with the apices inward ; the posterior tooth more truncated than 

 the others. The crowns of the first two can not be distinguished from those of the 

 superior molars. In the specimen No. 4, the first molar is less triangular than in 

 No. 2, resembling rather the third tooth, while the second is triangular. The 

 inferior molars of M. jeffersonii are incompletely known, the second being absent 

 from the best-known jaw, the one figured by Leidy. The first and third only differ 

 from those of the skull of M. wheatleyi, just mentioned, in their superior size. 



For the cranial characters of M. wheatleyi I must depend on specimen No. 4, 

 which is badly distorted, and the muzzle of both jaws broken off. 



Considerable differences between this skull and that of M. jeffersonii are 

 observable in the posterior regions. Thus, in the latter, the posterior side of the 

 paroccipital region is strongly excavated ; in M. wheatleyi it is flat, Within the 

 paroccipital process the fossa, which is present in both species, is separated by a 

 space from the sphenoid bone which differs materially in the two. The mastoid in 

 M- jeffersonii 'presents downward a keel, which is convex posteriorly and externally. 

 In M. wheatleyi this region is a transverse flat tuberosity bounding the insertion of 



