APPENDIX. 



Art. XXIY. — Notes on Mesozoic Vertebrate Fossils', by 

 O. C. Marsh. (With Plates II- Y) 



The extensive collections of vertebrate fossils from the 

 Laramie now under investigation by the writer contain, besides 

 those already described, many specimens of much interest, and 

 some of these are briefly noticed and figured in the present 

 article. The Dinosauria of this formation are of special 

 importance, particularly in their relations to allied forms in 

 the Jurassic, and hence some of the latter, also, are figured for 

 comparison. 



Claosaurus, Marsh, 1890. 



Next in importance to the Ceratopsidce of the Laramie are 

 the Dinosaurs allied to Hadrosaurus, and, as but little is 

 really known of the skeleton in this group, some of the 

 important parts are here ^described, and figured in Plates II 

 and III. These are mainly from a single specimen which is 

 in remarkable preservation ; but the remains of a second indi- 

 vidual, likewise in good condition, and in some respects more 

 perfect, have also been used in the investigation. The species 

 is Claosaurus an?iectens, already briefly described by the 

 writer.* 



The skull will be described in a later communication. The 

 number of vertebrae between the skull and sacrum is thirty, 

 and all were found . in position. There are nine vertebrae in 

 the sacrum, thoroughly coossified with each other. The anterior 

 forty-five vertebrae of the tail were found in position, and in 

 good preservation. 



* This Journal, vol. xliii, p. 453. May, 1892. 



