eopo.] ^"±0 £Dcc. •:, 



Measurements. M. 



Lengtli proximal limb No. 1 , 0.027 



Depth at base first tootli 01 



Width limb at micldle 008 



Length limb No. 2 017 



Depth at first tooth ^ 0058 



Length tooth series 0135 



Width third tooth basis 005 



These teeth indicace a species of about the size of the carp {Cyx>rinu& 

 carpio). 

 From Catharine's Creek, Idaho. Mus. no. 9792. 



DiASTicHtra pakvidens. Cope sp. nov. 

 In this species the bases of the teeth are considerably smaller than in 

 the last, and the proximal limb of the pharyngeal bone less depressed, 

 and more cylindric. A section of the latter below the basis of the first 

 tooth, is a triangle, the inner side a little shorter than the others. In the 

 last species it is flat in that place. 



M. 



Depth limb at first tooth '. , . .0-011 



Width hmb at middle tooth 0C65 



Length tooth series 014 



Length basis third tooth 0054 



This species is represented by one pharyngeal bone of the right side, 

 ■with the extremities incomplete, associated with many fragments of the 

 cranium, etc. The size the same as that of D. macrodon. 



No. 9782, Catharine's Creek, Idaho. 



The peculiar arrangement of the tooth series in this genus, almost at 

 right angles to that which is usual among Cyprinidse. is not, so far as I 

 know, shared by any recent genus of the family. 



OLIGOBELTJS. Cope. 



Genus novum. 



The direction of the dental series in this genus is intermediate between 

 that seen in Diastichus, and the usual tyjpe. It resembles and exceeds 

 the last described genus in the great elongation of the proximal limb of 

 the pharyngeal bones, which are here considerably more curved. No 

 bone of the genus preserves its distal end or its teeth complete. The 

 bases of the teeth are round or oval, and not in close contact. It is 

 scarcely likely that there were more than three in the outer row, though 

 this is not certain. The proximal end of the series is abbreviated, as the 

 first tooth of the index row is opposite its first, and the second opposite 

 its second. The proximal end of the series is most elevated, but does not 

 project beyond the lateral plane of the bone. 



Should the outer series have embraced four teeth, a resemblance between 

 the form of this bone and that of Ericymba and Exoglossum can be 



