THE 



AMERICAN JOURNALOFSCIENCE 



[FOURTH SERIES.] 



Aet. XXXIX, — Stegosaurus imgulatus Marsh, recently 

 moimted at the Peabody Museum of Ycde University / 

 by KiCHAED S. Lull. (With Plate II.) 



[Contributions from the Paleontological Laboratory of Peabody Museum, 

 Yale University, New Haven, Conn., U. S. A.] 



Contents : 



Introductory. 

 I. The specimen. 

 II. The skeleton. 



III. Armament. 



IV. Central nervous system. 

 V. Eestoration in the flesh. 



VI. Measurements. 

 VII. Life conditions and relationships. 



There lias recently been mounted at Yale University an 

 almost perfect example of the armored dinosaur Stegosaurus, 

 in many respects the most grotesqvie reptile the world ever 

 saw. The interest lies not only in this, but in the fact that, 

 while well known in literature owing to the masterly restora- 

 tion upon paper by Professor Othniel C. Marsh, this recon- 

 struction constitutes the first actual assembling of the bones in 

 their proper relationships with, as usual, a somewhat different 

 result from the generally accepted conception of the animal. 



The genus Stegosaurus was first described by Professor 

 Marsh in this Journal in 1877, the description being based 

 upon the skeleton now mounted. Repeated articles by Marsh 

 added to our knowledge of the creatui'e until, in 1891, the first 

 attempt was made to restore the animal on paper with the 

 wonderfully accurate results attained by Marsh in so many 

 similar drawings. Some errors naturally creep in when one is 

 working entirely in one plane of space. These the actual 

 mounting of the skeleton bone by bone alone can rectify. 



Am. Jour. Sci.— Fourth Series, Vol. XXX, No. 180. — December, 1910. 

 34 



