MEMOLRS 
OF THE 
CARNEGIE MUSEUM. 
\/ Olb, Ie INO), 7 
OSTEOLOGY OF BAPTANODON (MARSH). 
By C. W. Gru~More. 
INTRODUCTION. 
The discovery of the existence in the Jurassic of North America of a representa- 
tive of the Ichthyosaurian reptiles was first announced by Professor O. C. Marsh in 
1879." Although fossil remains of these animals are very abundant in Europe 
where they have attracted the attention of naturalists for the past two centuries, with 
one exception’ it was not until this late date that they were reported from this coun- 
try. Notwithstanding that continued explorations in the Jurassic have brought to 
light many representatives of this group, with the exception of a few short papers 
nothing has been published concerning the skeletal features of these interesting 
reptiles. 
The skeletons are usually imbedded in exceedingly hard and refractory concre- 
tions and the bone is so thoroughly impregnated with the matrix, which it closely 
resembles in color and texture, that the work of preparation is exceedingly tedious. 
The difficulty in preparing the material for study may in a measure account for the 
apparent neglect of this group. 
The Jurassic [chthyosaurian material preserved in the vertebrate collections of 
this museum has been largely gathered by the different field parties which have 
been operating for the past five seasons in the fossil deposits of the west. 
Through the courtesy of Mr. J. B. Hatcher, late Curator of the Department of 
Vertebrate Paleontology of the Carnegie Museum, this material has been placed at 
the disposal of the writer for study and description. 
1 Marsh, O. C., ‘‘ A New Order of Extinct Reptiles (Sauranodonta) from the Jurassic of North America,’’ Amer. 
Jour. Sci. (3), Vol. XVII., pp. 85-86, January, 1879. 
2 Leidy, Joseph, *‘ Notice of Some Reptilian Remains from Nevada,’’ Proc. Acad. Nat. Sci. Phila., Vol. XX., pp. 
177, 178, 1868. A Triassic form. 
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