276 Annals of the Carnegie Museum. 



Professor Marsh associated the skulls, which he had studied, with the 

 remains of Brontosauriis as the result of a process of ratiocination, 

 rather than as the result of ocular evidence that the skull actually 

 belonged with the skeleton. The only circumstance which would 

 seem to confirm the correctness of Marsh's view is the fact, to which 

 my attention is directed by Professor Lull, that when taking up the 

 remains of the Brontosmirus now on exhibition in the American 

 Museum of Natural History he found in the deposit a tooth evidently 

 belonging to the same genus, the skull of which Marsh has associated 

 with the skeleton of Brontosaurus. Professor Lull is of the opinion 

 that Marsh made no error, and that the presence of this tooth in the 

 quarry, which Lull explored in Wyoming, attests the correctness of 

 the conclusions of Marsh. The writer of these paragraphs confesses 

 to feeling a certain measure of doubt and uncertainty as to the matter, 

 and is disposed to the view that we do not yet positively know what 

 really is the skull which should be attributed to the genus Brontosaurus, 

 and is strongly inclined, in spite of the opinion of Dr, Lull, to think 

 that perhaps an error has been made, and that Brontosaurus, which is 

 so like Diplodocus in many of its skeletal features, ma}' have had a 

 skull like that of Diplodocus, characterized by feeble dentition, 

 dentition, however, which is not inserted in the maxillae vertically as in 

 the case of Diplodocus, but which, as the skull before the writer at this 

 moment shows, was more or less procumbent. 



There is no intention in these paragraphs to dogmatize, but to 

 express a doubt, founded upon observation, as to the correctness of 

 Professor Marsh's surmise, which up to the present time has been 

 unquestioningly accepted. To sum the matter up, the writer does 

 not believe that any man is in a position to declare with positive 

 assurance that the skull heretofore attributed to the genus Bronto- 

 saurus actually belonged to it. The two skulls used by Marsh were 

 found, one four miles from the rest of his skeleton, the other about 

 four hundred miles from it. Were it not, as I have already intimated, 

 for Professor Marsh's action, the writer would be tempted to declare 

 that the skull of Brontosaurus was not very dififerent from that of 

 Diplodocus in its main structural features in view of the fact that the 

 skull in his possession lay only twelve feet from the cervical vertebrae 

 and other skeletal remains before him. We know that the specimen 

 we are mounting must have had a skull. If we refuse to afifix to it the 

 skull which lav within twelve feet of the cervical \-ertebrae, we must 



