828 



SCIENCE. 



[N. S. Vol. XII. No. 309. 



lations as his should have deterred his con- 

 temporaries from following his trend of 

 thought or paying much attention to him. 

 It cannot be claimed that he preceded Dal- 

 ton in his conception of the Atomic Theory, 

 but Eichter belongs to the number of the 

 great original thinkers of chemistry and it 

 is time that greater justice be done him. 

 r. P. Venable. 



VERTEBRAL FORMULA OF DIPLODOCUS 

 {MARSH). 



The splendid skeleton of Diplodocus, dis- 

 covered in the Como Bluffs of Wyoming by 

 the American Museum party of 1897, has 

 enabled Professor Osborn to very materially 

 increase our knowledge of the osteology of 

 that genus. ^i^ Interesting and unique as was 

 the material that formed the basis of Pro- 

 fessor Osborn's memoir, it nevertheless left 

 many questions unsettled concerning the 

 osteology of Diplodocus. In 1899 a second 

 skeleton was discovered in the Dinosaur 

 beds of the Upper Jurassic, near Sheep 

 Creek, in Albany Countj'^, Wyoming, by Dr. 

 J. L. Wortman, while engaged as Curator of 

 Vertebrate Paleontology of this Museum, 

 in exploring the fossil-bearing horizons of 

 that region. 



The second skeleton of Diplodocus was 

 very carefully exhumed under the skillful 

 direction of Dr. Wortman, and has since 

 been entirely freed from the matrix and 

 temporarily mounted by Mr. A. S. Cogges- 

 hall. Chief Preparator in the Department 

 of Paleontology. 



Now that this material is available for 

 study, it proves to supplement in a remark- 

 able manner the skeleton belonging to the 

 American Museum. A detailed descrip- 

 tion of our material will be given in a 

 paper by the writer which it is proposed to 

 have appear among the memoirs of this in- 

 stitution. In the present note only the 



•See 'A Skeleton of Diplodocus,' Part V., Vol. I., 

 Mem. Am. Mus. Nat. Hist., pp. 191-214 



vertebral column will be considered, and no 

 attempt will be made to describe this in de- 

 tail, but rather to correct some errors con- 

 cerning the vertebral formula of Diplodocus 

 as given by Osborn in his memoir cited 

 above, and by Dr. W. J. Holland, in a subse- 

 quent paper entitled ' The Vertebral For- 

 mula in Diplodocus, Marsh,' published in 

 this Journal, May 25, 1900, and based upon 

 the material now under discussion. 



About 45 feet (14 meters) of the verte- 

 bral column is preserved in our specimen. 

 When discovered the vertebrae did not lie 

 in a connected and unbroken series, yet 

 there can be little doubt that they all per- 

 tain to the same individual, and they have 

 been mounted as a continuous series com.- 

 mencing with the axis and ending with the 

 twelfth caudal. In all 41 vertebrae are repre- 

 sented, including 14 cervicals (all but the 

 atlas), 11 dorsals, 4 sacrals and 12 caudals. 



Assuming that no vertebrae are missing 

 from our series the vertebral formula of 

 Diplodocus should now be written as fol- 

 lows: 



Cervicals, 15. 

 Dorsals, 11. 

 Sacrals, 4. 



Caudals, 37, as estimated by Osborn, not 35, as 

 attributed to him by Holland. 



The above vertebral formula will be seen 

 to differ from that given by Holland, the 

 latest contributor on this subject, as follows : 



1. The number of cervicals is at least 15. 



2. There are 11 dorsals instead of 10, as 

 fixed by Holland, who mistook the first 

 presacral of Osborn for a sacral. 



There are 4 sacrals, as given by Osborn 

 and Holland, while the number of caudals 

 is still placed at 37, as estimated by Osborn. 

 Of the caudals, only the 12 anterior are 

 preserved in our skeleton, and the second 

 and third of these have coossified centra. 



In placing the number of dorsals at 11, I 

 am assuming that Osborn is right in con- 

 sidering the first vertebra with a free spine, 



