NUMERICAL VARIATION IN THE HUMAN SPINE. 311 



V. Variations, wliich separately seem either reversive or progressive, generally lose 

 that appearance when the whole spine is considered. 



VI. After the occurrence of the original error in development there is a tendency 

 for the spine to assume as nearly as possilile its normal disposition and proportions. This, 

 as do also concomitant variations and indeed all development, implies a \dtal principle. 



I wish to express my sincere thanks to Dr. H. P. Mosher for the great care he has 



taken with the drawings. 



The following tables are to enable the reader to find the account of any spine or 

 incomplete specimen that may be referred to in any part of the paper. 



Spine Page Sitine Pag:e Si»ine I'age 



1 249 350 287 729 251 



2 259 361 256 764 263 

 21 254 377 285 A-4 262 

 24 275 381 207 A-7 282 

 85 285 478 288 A-30 249 

 110 265 492 279 A-175 259 

 141 282 493 266 A-186 264 

 202 294 504 264 A-219 281 

 208 268 545 261 D-7 284 

 257 279 561 255 G-19 247 

 264 273 567 248 G-22 258 

 267 290 578 265 H-3 276 

 297 270 615 246 X 256 

 306 252 636 247 Y 266 

 349 278 649 250 Z 274 



BlBLIOGRAniY. 



Albrecht, Paul. 



'84. Sur le.s elfmeuts morphologiques du manubrium du sternum chez les mammiferes. Libre jubilaire pubiie par la 

 Societfi de Medicine, Gand, k Toccasion du 50e anniversaire de sa fondation. P. 157. 

 Bateson, William. 



'94. Materials for the .study of variation, treated with especial regard to discontinuity in the origin of species. 

 London. 8°. lUus. 

 Baur, G. 



'91. On intercalation of vertebrae. Journ. of morph., vol. 4, pp. 331-336. 



'97. Remarks on the question of intercalation of vertebrae. Zool. bull., vol. 1, pp. 41-55. 



