PLECTOSPONDYLI. 751 



obliquely truncate in profile. Dorsal fin elong-ate, elevated in front ; radii 

 mostly short; caudal openly emarginate ; anal not very elongate in either 

 direction ; ventrals below first rays of the dorsal. Radii, D., Ill, 31 ; A., 

 II, 11. Scales, J^Jj, with concentric and radiating lines well developed 

 Vertebrae .6, 17, 10. 



Measurements. 



M. 



Total length 0.112 



Length to basis of caudal 093 



Length to basis of anal (axial) 071 



Length to basis of ventral (axial) 041 



Depth of caudal peduncle 015 



Depth of antei ior anal rays 022 



Depth at occipital crest 030 



In another rather larger specimen, which agrees with that above de- 

 scribed, the lateral lines are well preserved. 

 From the South Park, Colorado. 



Amyzon fusiforme Cope. 



Bulletin U. S. Geol. Survey Terrs., 2d series, 1875, p. 5. 



Represented by a very small fish, which exhibits fully ossified bones, 

 but may be immature. It exhibits characters quite distinctive, although 

 the caudal peduncle, anal fin, and opposite parts of dorsal, are wanting. 

 The head is very perfectly preserved, and is of a regularly short conic form, 

 with equal lips. The attenuated muzzle shows none of the obtuseness char- 

 acteristic of the other Amyzon s. Another peculiarity is seen in the ventral 

 fins, which stand below the eighth instead of the first articulated dorsal ray. 

 They are evidently in their normal position, and the ribs are undisturbed. 

 The pectorals extend more than half way to the ventrals. There are seven 

 neural spines in front of the first interneural, and sixteen between the latter 

 and the first interhsemal. In this, as in the other species, the postclavicle 

 is rather elongate and acute, and the parapophysial element of the anterior 

 vertebral mass extends as far down as the line of the middle of the orbit. 



Measurements. 



M. 



Length of head 0.0095 



Length to line of ventrals 0180 



Length to line of aual 0239 



Depth at first dorsal ray 0105 



Depth at occiput 0070 



From the South Park, Colorado. 



