2 22 Bulletin American Museum of Natural History. [Vol. X, 



over a considerable surface. The dorsal spines, and in some 

 cases the sides of the centra are found to be deeply gashed 

 with the sharp teeth of a carnivorous Dinosaur. The upper 

 portion of several spines, in fact, is entirely bitten away, the upper 

 surface containing jagged transverse grooves, which prove that the 

 carnivore was of great power, and applied its pointed teeth with 

 strong effect to the gristle and muscles upon the sides of this 

 prodigious tail. 



Table I. — Measurements of Vertebra. 



Anterior dorsal. 



Posterior dorsal. 



First caudal. . . . 



e 2d caudal 



e 5th caudal. .. . 



e 8th caudal 



e gth caudal 



e I2th caudal' . . . . 



e 13th caudal 



e 14th caudal 



e 1 6th caudal 



e 17th caudal., 

 e 20th caudal- . . . 

 e 2ist caudal-. . . . 



e 22d caudal'- 



e 23d caudal- 



e 24th caudal-'. . . . 

 e 27th caudal- . . . 

 e 28th caudal- . . . . 

 e 30th caudal- . . . . 

 e 31st caudal". . . 

 e 36th caudal- .. . . 

 e 40 total 



S'Sc 



? 



? 



162 

 164 

 168 

 177 

 167 

 179 

 170 



180 

 180 

 185 

 192 

 200 

 198 

 205 

 203 

 197 

 200 

 203 

 185 



6S 



6310 



368 

 383 



360 

 340 

 333 

 305 

 283 

 282 

 272 

 256 

 220 

 210 

 202 

 194 

 184 

 171 

 170 

 152 

 148 

 127 



310 

 340 

 335 

 6350 

 - 324 

 300 

 300 



274 

 260 



2^8 



248 

 228 

 205 

 194 

 186 

 176 



175 

 162 



155 

 146 

 136 

 115 



3^ 





'5. i* 1* 

 rt " > 

 u 



1050 

 1280 

 1075 



830 

 798 

 712 

 633 

 598 

 548 

 520 

 ■? 



470 



"3 ^ . 



J£ (y CJ 



(U 1^ £ 



3 O > 



H 



e864 

 6715 



957 



e695 



615 

 622 



587 



537 



505 



6444 



£395 



€265 



172 



137 



e.2 



<3&4 

 <6 & 7 



<IO&II 



<i5 

 <i8&i9 



<25&26 



<32&35 

 <37 



Note. — Many interesting facts are brought out by the exact measurements of the caudals 

 given in this Table. The centra decrease steadily in their transverse and vertical diameters, 

 but they increase steadily in the longitudinal diameter as far back as the 26th caudal, then 

 begins a decrease. Thus the estimated 31st caudal measures 203 mm.; the 36th caudal, meas- 

 uring 185 mm., probably marks the natural decrease towards the tip of the tail. A constant 

 ratio of decrease, however, characterized the dorsal spines. 



' Measurements agree approximately with supposed 4th caudal. Marsh. 

 '^ Summits of spines bitten off and grooved by large cutting teeth. 



