VERTEBRAL COLUMN 123 



lation. In these specimens the seventh lumbar has rudimentary ac- 

 cessory processes, the lamina? are longer than a normal seventh, and 

 the emargination between the caudal articular processes is less pro- 

 nounced. 



The sacrum may be increased by the addition of a vertebra to its 

 cephalic end or by the coalescence of the first vertebra of the tail with 

 its caudal end. In the former case the addition may be at the expense 

 of the lumbar region (Fig. 82), and thereby represent a more cephalic 



FIG. 82. 



'|!,|lB~ Transverse Process of Vertebra. 



11111 

 Auricular Surface. - 



SACRUM PARTIALLY UNITED WITH SEVENTH LUMBAR VERTEBRA. 



attachment of the pelvic girdle to the axial skeleton, or the addition 

 may be associated with an increase in the number of the lumbar 

 vertebra?, and thereby represent an attachment of the pelvic girdle 

 more than usually caudal. 



Coalescence of the caudal vertebrae with the sacrum has been 

 noted ; more frequently, however, the last sacral is free, either com- 

 pletely or still showing traces of coalescence between the transverse 

 processes. 



The caudal vertebrae are subject to some variation in number, 

 probably not to the extent commonly supposed ; it is difficult to 

 preserve the small terminal ossicles. The relation between the varia- 

 tions in number and the variations in their peculiar features is shown 

 in the following table. The vertebrae are numbered from the sacrum, 

 and those which are indicated by bold-faced type exhibit the features 

 most distinctly. 



