184 University of Kansas Geological Survey. 



ing with its fellow of the other side, forming a production of 

 the roof of the neural canal. The combined keels become con- 

 tinuous with the anterior acute edge of the neural spine. Thus 

 the form is quite different from that seen in P. muclgei, and 

 constitutes a lower grade of rudiment. The fact that this zygo- 

 sphenal roof is separated on each side from the zygapophyses by 

 an acute groove gives the former a distinctness more apparent 

 than real : 



" Length of median cervical 43mm. 



Diameter of the ball of a median cervical, vertical 20 



Diameter of the ball of a median cervical, transverse 33 



Length of the anterior dorsal 42 



Width of the cup 32 



This species was from Butte Creek, " fourteen miles south of 

 Fort Wallace/' If this locality is correctly given it may be 

 that the horizon is Fort Pierre. The author speaks of the 

 species as the "smallest known Platecarpus." A second speci- 

 men, discovered by Mudge from the vicinity of Sheridan, must 

 necessarily be of the Fort Pierre. The material is so very frag- 

 mentary from both of these localities that I cannot venture an 

 opinion as to the exact affinities of the species. If a Platecarpus, 

 it is probably distinct from any others. 



Platecarpus ictericus. 



Holcodus ictericus Cope, Proc. Amer. Phil. Soc, 1870, 577; ibid., Dec. 1871. 

 Lestosauras ictericus Marsh, Amer. Journ. Sci., June, 1872. 

 Platecarpus ictericus Cope, Cret. Vert., 149, 267, pi. xiv, f. 4; xv, f. 2; xvn, 

 ff. 3, 4: xviii, f. 6: xix, f. 9; xx. f. 1: xxv: xxxvi, f.7: xxxvn, f. 6. 



This species was the first of the genus described from Kansas. 

 Several specimens in our collection may be referred to it with 

 tolerable certainty. Just what the essential specific characters 

 are I am not prepared to state. The size, however, which is 

 materially greater than any other, is apparently constant. 



In pi. xliv is given a figure of the front paddle, repro- 

 duced from a drawing made in the field by myself in 1875. I 

 cannot say at this time that the drawing is accurate in all de- 

 tails, but from the care taken in its production I believe that it 

 is. It was made natural size, and bears the following in my own 

 writing: "Found by Prof. B. F. Mudge, South Fork Solomon 



