190 

 The measurements of the specimen are as follows : 



Lines. 



Length of centrum iuferiorly . . 8. 6 



Breadth of ceutrum posteriorly 8. G 



Height of ceutrum i)osteriorly — , CO 



Another specunen, consisting of a caudal centrum, perhaps belongs to the 

 same species. It has about the same length as the preceding, and is hexa- 

 gonal in outline at the ends. Its sides present a strong longitudinal ridge 

 separating a deep fossa below from another above. 



The measurements of the specimen are as follows : 



Lines. 



Length of centrum interiorly 8. 4 



Breadth of centrum posteriorly 4. 4 



Height of centrum ijosteriorly 4. 8 



Lepidosteus ? 



Accompanying the preceding specimens there are two vertebrae of another 

 species of Lepidosteus. One of them is a posterior dorsal centrum, and is 

 represented in Figs. IG, 17. It is about as long as the corresponding centra 

 of the gar-pike, Lepidosteus osseus, but is ^jroportionately broader and more 

 robust. Its articular ends are hexahedral, with the upper and lower borders 

 slightly emarginate. The lower surface of the centrum is nearly flat, nearly 

 level, contracted at its anterior third, and deeply grooved along the middle. 

 It is bounded by ridges defining it? from the deeply impressed sides. 



The other specimen is the centrum of a caudal nearly as long as the former, 

 but narrower in proportion with its difference of position in the series. 



The measurements of the specimens are as follows : 



Lines. 



Length of dorsal centrum iuferiorly 5. 4 



Length of caudal centrum iuferiorly , 5. 



Breadth of dorsal centrum posteriorly 5.4 



Breadth of caudal centrum posteriorly 3. 



Height of dorsal centrum posteriorly 4.2 



Height of caudal centrum posteriorly 3. 2 



These specimens may, perhaps, belong to one of the species indicated by 

 Professor Marsh. 



Figs. 27 to 30 represent several ganoid scales, accompanying the preceding 

 specimens, which probably pertain to the smaller of the two Lepidostei. 

 They are covered \\itli perfectly smooth, shining ganoine without markings. 



Fig. 25 represents a fragment of the fore part of the right ramus of the 

 lower jaw accompanying the former specimens. Its construction is similar 



