HOLLAND : THE OSTEOLOGY OF DIPLODOCUS MARSH 253 
Fork of Powder River, in finding the tail of a Diplodocus with the caudal vertebree 
articulated and succeeding each other in regular order from very near the extrem- 
ity of the tail forward to a point considerably beyond its middle. The study of this 
series of caudals in connection with the three other specimens acquired by the Car- 
negie Museum reveals the fact that the number of vertebree estimated by Professor 
Osborn falls far short of the true number. In making the restoration which has 
been placed in the British Museum we utilized the twelve anterior caudals belong- 
ing to specimen No. 84 (Carnegie Museum Catalogue of Vertebrate Fossils) which 
had been found articulated and in the position held in life. From the caudal ver- 
tebree found in connection with specimen No. 94 (Carnegie Museum Catalogue of 
Vertebrate Fossils) we selected nineteen caudals corresponding to the caudals be- 
longing to the very beautiful specimen in the American Museum of Natural His- 
tory which are figured by Professor Osborn and which when placed in position 
showed normal relationships to the anterior caudals, the position of which was ab- 
solutely ascertained, as well as to each other. The caudal No. 32 was supplied 
from the material obtained by Mr. Utterback on the Red Fork of the Powder 
River, belonging to specimen No. 307 (Carnegie Museum Catalogue of Vertebrate 
Fossils). Caudals 33 to 86 inclusive were taken from specimen No. 94. Caudals 
37 to 73 inclusive represent the series found articulated and in position by Mr. 
Utterback in 1903. (See Plate X XIX.) 
We were induced to select the vertebree used in the caudal series taken from 
specimen No. 94 (Carnegie Museum Catalogue of Vertebrate Fossils) because of the 
fact that the specimen from which they were taken, though slightly smaller than 
specimen No. 84, corresponded more nearly in size to that specimen than caudals 
belonging to the specimens which were subsequently found. Caudals from 37 to 73 
inclusive represent a specimen, which, judging from other bones (not vertebree), 
which were found in connection with its caudal series, was a decidedly smaller in- 
dividual than specimen No. 84, and even smaller than specimen No. 94. The total 
length of the caudal series made up in the manner which has been described, al- 
though at the first glance calculated to fill the observer with astonishment, is very 
probably shorter than the entire series would have been, had the specimen No. 307 
attained as large a size as the other specimens which were utilized. Furthermore, 
in spite of the enormous prolongation of the tail which is shown, it is positively 
ascertained that not all of the vertebrae belonging to the caudal series are repre- 
sented in it. The last caudal in the series plainly shows an articulation at its pos- 
terior extremity for the attachment of another caudal, and there may have been 
several succeeding it. 
