Apr. 1903. NortTH AMERICAN PLESIOSAURS—WILLISTON. 13 
DOLICHORHYNCHOPS OSBORNI. 
The specimen of Dolichorhynchops 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 nowis. 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, anda 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 
vertebre. The position as shown in the restoration is that which 
seemed, upon the whole, most nearly the truth, judging from the 
figured skeletons of Plestosaurus. 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 vertebre 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 there are thirty vertebra, three of 
which may be 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 
