On the Dermal Covering of Hesperornis. 



BY S. \V. WILLISTON. 



(With Plate II.) 



A specimen of Hesperornis, collected in western Kansas the past 

 year by Mr. H. T. Martin and now in the University Museum, is 

 of especial interest from the information it affords of the dermal 

 covering of this Cretaceous toothed bird. 



The specimen, which is in excellent preservation, lies upon a 

 chalk slab, with the head doubled partly under the pelvis. Some 

 six or eight vertebrae, together with the humeri and coracoids and 

 many of the ribs are wanting; otherwise the specimen seems 

 perfect. The size is distinctively less than that of H. regalis, and 

 it does not seem to be due to immaturity. Possibly the species is 

 identical with H. gracilis, which has been only imperfectly de- 

 scribed. 



The photographic illustration given in Plate II was taken from 

 the fragment removed from the slab over the right tarso-metatarsal, 

 the surface of the slab itself being less clearly, though more fully 

 marked. I have sketched in the bone to show the relative size and 

 position. 



The podotheca is seen to be scutellate in front. The structure 

 is shown so clearly in the photograph that I need not enter into a 

 fuller description. The scutes are all smooth, not imbricated, and 

 distinctly separated from each other. They are a little longer 

 from side to side below, though not much. I count twenty-six on 

 the slab, and to the back part of the bone, while impressions of 

 the feathers will be seen on the opposite side. 



These feathers were evidently long, reaching nearly to the 

 phalangeal articulation, and are clearly semiplumulaceous in 

 character, the pennaceous shaft of considerable size, the vanes 

 long and wavy. The shaft of one feather is seen in the illustration 

 lying close to the outline of the bone, and is of considerable size. 

 I doubt not that the feathers throughout were of this character, or 

 wholly plumulaceous. I find distinct impressions of the wavy 

 vanes at the back of the head and elsewhere, but in no case is 

 there the impression of a true feather, as I think would surely be 

 the case had the bird possessed them. 



(53) KAN. UNIV. QUAR., VOI-. V, NO. I, JULY, 18%. 



