VERTEBRATA FROM THE NEOCOMIAN Ol' KANSAS. 73 



of the plate which bears tlie denticles, its general surface 

 minutely and unevenly striate and punctate-striate, there 

 being on the anterior part, a little back of the border (on one 

 side only as preserved in the type-specimen) one or two nar- 

 row, low, longitudinal folds, or carina-like ridges; the greatest 

 breadth of the cross-section of the spine in the posterior part 

 of the denticuliferous portion contained twice in the length 

 of that section: denticles proportioned, arranged, and recurved 

 somewhat as in H. reticalatus, Ag., as figured by Zittel, their 

 compressed convex border with delicate but salient carina, 

 their broader, concave border rounded. 



For minor details, see illustrations, of which figs. 11-13 

 are in part restored, and fig. 14 is a cross-section. The smaller 

 and more compressed denticles in fig. 12 represent the average 

 size of the denticles more accurately than the large ones. 



Measurements. — Greatest breadth of the preserved part 

 of spine 13 mm. The entire length of the spine (of which 

 a length of a little more than 60 mm. is preserved) cannot 

 have been much less than a foot. 



Occurrence. — The type-spine of this species was found 

 and presented to the writer by a member of the family of 

 Mr. W. E. Brown, in Clark county, Kansas, in the area of the 

 outcrop of the Fredericksburg Cretaceous shale, at the south 

 end of the "Amphitheatre" mentioned in connection with the 

 above-cited " Blutf Creek section." 



