Apr. 1903. North American Plesiosaurs — Williston. 13 



DOLICHORHYNCHOPS OSBORNI. 



The specimen of DolichorJiynchops osborni herewith described and 

 illustrated was discovered by Mr. George Sternberg in the chalk of 

 Logan County, Kansas, in the summer of 1900, and skilfully collected 

 by his father, Mr. Chas. H. Sternberg, the veteran collector of fossil 

 vertebrates. The specimen was purchased of Mr. Sternberg in the 

 following spring for the University of Kansas, where it has been 

 mounted and where it now is. When received at the museum the 

 skeleton was almost wholly contained in a large slab of soft yellow 

 chalk, with all its bones disassociated and more or less entangled 

 together. The left ischium, lying by the side of the maxilla, was 

 protruding from the surface, and a part of it was lost. The bones of 

 the tail and some of the smaller podial bones were removed a little 

 distance from the rest of the skeleton, and were collected separately 

 by Mr. Sternberg. The head was lying partly upon its left side and 

 some of the bones of the right side had been macerated away; the 

 maxilla indeed had disappeared. 



The task of removing and mounting the bones has required the 

 labor of Mr. H. T. Martin the larger part of a year, and is, as finally 

 mounted, an example of great labor and skill on his part. For the 

 position of the bones in the recreated skeleton and their general 

 arrangement I am of course responsible. There is some little doubt 

 as to the exact position of the pectoral girdle, as respects the ribs and 

 vertebrae. The position as shown in the restoration is that which 

 med, upon the whole, most nearly the truth, judging from the 

 figured skeletons of Plcsiosaurus. There is also some doubt about 

 the proper length of the tail. The relations of the preserved centra 

 seemed to indicate a loss of a few vertebrae in this region, and for 

 that reason four plaster models have been intercalated. There are 

 nineteen vertebrae preserved in the neck; there may have been one 

 more, or possibly two, but for reasons discussed further on this is 

 doubtful. In the dorsal region their are thirty vertebrae, three of 

 which maybe called pectoral. Twenty-five are preserved in the tail. 

 The skull, after its complete removal from the matrix, was found 

 to be so very fragile that it was not thought expedient to mount it. 

 It was also somewhat distorted, as will be seen from the illustrations. 

 A model, therefore, was made under my careful supervision, and 

 mounted in its stead. The skeleton as mounted is just ten feet in 



