Notice of JVew Dinosauria. 335 



the family. Other remains received more recently indicate 

 forms much larger, and more grotesque in appearance. They 

 also afford considerable information in regard to the structure 

 of these animals, showing them to be true Stegosauria, but 

 with the skull and dermal armor strangely modified and 

 specialized just before the group became extinct. 



The vertebrae, and the bones of the limbs and of the feet, 

 are so much like the corresponding parts of the typical 

 Stegosaurus from the Jurassic, that it would be difficult to 

 separate the two when in fragmentary condition, as are most 

 of those from the later formation. The latter forms, however, 

 are of larger size, and nearly all the bones have a peculiar 

 rugosity, much less marked in the Jurassic species. In the 

 form here described, this feature is very conspicuous, and 

 marks almost every known part of the skeleton. 



In the type specimen of the present species, the posterior 

 horn-cores are much larger than these appendages in any other 

 known animal, living or extinct. One of them measures at 

 the base, no less than twenty-seven inches, and about sixteen 

 inches around, half way to the summit. Its total height was 

 about two feet. In general form, these horn-cores resemble 

 those of Ceratops montanus, but the anterior margin is more 

 compressed, showing indications of a ridge. 



The top of the skull, in the region of the horn-cores, is thick 

 and massive, and strongly rugose. 



This skull as a whole must have had at least fifty times the 

 weight of the skull of the largest Sauropoda known, and this 

 fact will give some idea of the appearance of this reptile when 

 alive. 



As previously stated, the posterior pair of horn-cores of this 

 family are hollow at the base, and in form and surface mark- 

 ings are precisely like those of the JBovidw. The resemblance 

 is so close that, when detached from the skull, they cannot be 

 distinguished by any anatomical character. This accurate 

 repetition, in later and still existing forms, of the highly special- 

 ized weapons of an extinct group of another class is a fact of 

 much interest. 



The present specimen is from the Laramie formation of 

 "Wyoming, but fragmentary remains, which may be referred 

 provisionally to the same species, have been found in Colorado. 



Hadrosaurus hreviceps, sp. no v. 



An interesting specimen in the Yale University Museum, 

 from Montana, indicates a large Dinosaur, apparently belonging 

 to the genus Hadrosaurus, and hitherto unknown. It is the 

 dentary portion of the right maxillary, and is so characteristic, 

 that it is here briefly described and figured. Its main features 

 are well shown in figures 4 and 5 below. 



