Peterson: Material Discovered in Uinta Basin. 



119 



greater portion of P:j-, and fragments of the molars. As already 

 stated, the specimen was found in a mutilated state, there being 

 neither upper or lower incisors present. The specimen in the Ameri- 

 can Museum, No. 1828, already referred to, supplements the present 

 specimen admirably. The symphysis of this specimen does not fit 

 upon the back part of the jaw, due to loss of contact. If the speci- 

 men (See Fig. 17), pertains to the same individual, which appears quite 

 likely, it is clear that there are two well-marked species of Isectolophus 

 in the Uinta sediments. One of these has a long diastema back of the 

 canine and the symphysis itself is constricted transversely as in 

 Triplopus, while the other species has no diastema and no constriction 

 of the symphysis. 



The incisors and canine of the specimen in the American Museum 

 are represented by roots only. These roots are of subequal size and 

 have about one-half the diameter of the canine. Both incisors and 

 canines had apparently a procumbent position. Back of the canine 

 there is, as already stated, a long diatema with sharp superior border. 

 The premolars are not present, while the molars are well-represented 

 in this specimen. In comparing the molars with those of the type of 

 Isectolophus it is at once clear that they pertain to Isectolophus annec- 

 tens from their size and detailed structure. 



P-j- of the specimen in the Carnegie Museum, No. 3030, is quite 



Fig. 17. Isectolophus annectens. No. 1828 American Museum of Natural History. 



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molariform, except for the lack of the tetartoconid. The cross-crests 

 of the lower molars are perfect, as is the case in the specimen in the 

 American Museum, and the third lobe (hypoconulid) of M-j is large, 

 as in the type. The only noteworthy difference between No. 3030 



