235 



Measurements of No. 3. 



M. 



Length of eighteen of the dorsal vertobrao ., 0.275 



Length of eighteen of the caudal vertebra} 0. 320 



Depth of the head at the opercular borders 0. 155 



Longitudinal width of tho operculum 0.050 



Length of tho abdominal dermal scutum 0. 050 



Width of the abdominal dermal scutum 0.014 



Numerous specimens from Professors Merrill and Mudge, and collected 

 by myself during the expedition of 1871. 



PHASGANODUS, Leidy. 



The characters of this genus are as yet but little known; but isolated 

 teeth may be known by the existence of a straight cutting-edge in front, and 

 shorter one extending downward from the apex behind, to different lengths 

 in the different species. The form is near to Enchodus, especially in the 

 elongate anterior teeth; but, in that genus, the long teeth have unsymmetrical 

 cutting-edges, which are not in the long axis of the dentary bone. 



Phasganodus cakinatus, Cope. 



Founded on a shed example of one of the long teeth, taken from the 

 matrix attached to the dorsal vertebras of the Elasmosaurus platyurus. The 

 tooth is more elongate in outline than that of the S. speciosa, Leidy, I. c; more 

 than twice as long as wide at the base. The anterior margin is the more 

 oblique, and its smooth face is margined by a faint line posteriorly, and is 

 continued to the extremity. The convex inner face of the tooth behind is 

 sculptured with a few fine deep grooves, which are separated by acute ridges, 

 which do not extend over more than half the length of the tooth. Length, 

 three lines. 



From the Upper Cretaceous of the neighborhood of Fort Wallace, Kans. 



Phasganodus gladiolus, Cope. 



Represented by a single elongate tooth, which is intermediate in charac- 

 ter between those of the two species last described, but much larger than 

 either. It is large for an anterior maxillary tooth of Phasganodus anceps, 

 and, should it pertain to the end of the mandibular series, will in so far 

 resemble the genus Enchodus; but the cutting-edges are opposite, to each 

 other, and not, as is usual in that genus, on one side, leaving the inner face 

 very convex. In this species, the crown is rather slender, and compressed 



