No. 502] HABITS OF SAUROPODOUS DINOSAURS 675 



To the present writer the suggestion of Dr. Holland 

 has in it more of probability than any of the others pre- 

 sented. If the food-plants sought by Diplodocus had 

 been large and such as required uprooting by the great 

 claws of the reptile the prehension and manipulation of 

 the masses would have been liable to break the slender 

 teeth and would certainly have produced on them per- 

 ceptible wear. The upper teeth of the original of Marsh's 

 figures on Plate XXV of the Dinosaurs of North Amer- 

 ica 6 show no wear, so far as the writer can determine. 

 The mandibular teeth are not well exposed to view. 



With respect to Osborn's theory, it is well to take into 

 consideration also the probable ability of the reptile to 

 digest great masses of undivided and unmasticated vege- 

 tation. Against the theory suggested by Knight's res- 

 toration it may be urged that the teeth, pointed or slightly 

 chisel-shaped, are poorly adapted for cropping leaves 

 and great buds; most of all, the teeth have spaces be- 

 tween them, like the teeth of a great comb, an arrange- 

 ment not favorable to their functioning as cutting instru- 

 ments. The teeth could hardly have been used for 

 scraping alga* from rocks, either, for that usage would 

 have produced evident and rapid wear. It is more 

 probable that the food consisted of floating algae and of 

 plants that were loosely attached to the bottoms of stag- 

 nant bayous and ponds. Hatcher has reported 7 the 

 finding of the seeds and the stems of a species of Chara 

 near the Marsh quarry, where many Sauropoda have 

 been found. This alga, it seems to the writer, would 

 have been admirably adapted to the needs of Diplodocus. 

 It could be easily gathered into 'the mouth as the reptile 

 swam or crawled lazily about or rested itself and re- 

 tracted and extended its long neck. The long and highly 

 vaulted palate would have permitted a considerable mass 

 to be collected, out of which, by pressure of the tongue, 

 the superfluous water might have been squeezed between 



1 (Cat. No. 2672, U. S. Nat. Mus.) 

 T Mem. Carnegie Mus., II, p. 63. 



