336 



Notice of New Dinosauria. 



The teeth are very numerous, and form a tessellated surface, 

 as in Hadrosaurus Foulkii, Leidy, but they are more elongate, 

 and the outer enamelled faces ard less distinctly rhomboid in 

 form. The grooves, also, in which the inner surfaces of the 

 fangs were inserted, are less regular, than in that species. 



Fig. 4. 



Fig. 5. 



Figure 4. — Right maxillary of Hadrosaurus breviceps, Marsh ; outside view. 

 Figure 5. — The same jaw ; showing worn surface of teeth. 

 Both figures are one-fourth natural size. 



The present specimen is from the Laramie formation of 

 Montana. 



Hadrosaurus paucidens^ sp. no v. 



In strong contrast with the species above described is 

 another from the same region and same formation. The best 

 preserved specimen that now represents it is a left maxillary, 

 nearly complete. With this was found some other portions of 

 the skull, but the maxillary affords the best distinctive char- 

 acters. All, however, indicate a skull of extreme lightness 

 and delicacy of build for one of the Ornithopoda. The max- 

 illary is especially slender, and the anterior and posterior ex- 

 tremities are pointed. The middle of the bone is more mas- 

 sive, but yet very light for this portion of the skull. The 

 teeth are of the general type of those in this genus, but are 

 comparatively few in number, and only one row appears to 

 have been in service. 



The maxillary preserved is about ten inches in length, and 

 three inches high near the center. The row of teeth in use 

 contains about thirty. 



The remains on which the present species is based were 

 found in 1888, in the Laramie formation of Montana, by Mr. 

 J. B. Hatcher, of the United States Geological Survey. 



New Haven, Conn., March 25, 1889. 



