478 BUMPUS. (Von. XII. 
questioned both by Bateson and Parker, though believed by 
Rosenberg and Credner. With Parker one can agree that the 
“sacral region has the power of developing sacral ribs at sev- 
eral points on both right and left sides.” But Parker gives us 
no reason for the abnormal position often taken by certain 
sacral ribs, and does not explain why a particular vertebra (or 
vertebrae) produces sacral ribs, and why others, potentially able 
to produce sacral ribs, produce ribs of the ordinary sort. If 
several vertebrze are endowed with this power, why do we 
never find nicely formed sacral ribs passing out into the sur- 
rounding tissue as if searching for some ilia with which they 
might articulate, and why are the ilia not occasionally attached 
to ribs of the ordinary triangular type? 
The sacrum, pelvis, and appendages are not intimately asso- 
ciated parts of the body that represent one complete whole, and 
the definitive location of the sacrum is probably due to cen- 
tripetal influence derived from the budding appendage. Inter- 
calation in the sense of the introduction of new segments does 
not take place, and what have been given as examples of inter- 
calation are probably only imperfectly formed body segments. 
BROWN UNIVERSITY, PROVIDENCE, R. I. 
Nov. 3, 1896. 

