126 



ALES' HRDLIKA 



other bones must be sought for, first, in original differences in the 

 attachment of the various muscles to the shafts; and second, in an 

 unequal development and work of the individual muscles during child- 

 hood and adolescence. The original differences in attachment, 

 some of which can be clearly seen on the bones, are in all probability 

 partly hereditary, partly early acquired conditions. The manner 

 in which the differently attached or differently developed muscles 

 affect the shape of bone must of course be largely if not entirely 

 mechanical. 



ADDITIONAL OBSERVATIONS 



In addition to shape, the bones of the skeleton offer an array of 

 highly interesting points for observation, and many of these, as 

 already mentioned, are of phylogenetic importance. Of these, the 

 main ones will be included in the blanks to be given. 



MEASUREMENTS 



Blank: HUMERUS 



Tribe Locality Observer, 



Right 



Left 



1 Type 1 = prismatic; 2, 2a = lateral prismatic (2 = posterior surface facing 

 backward and inward; 2a = posterior surface facing backward and outward); 4 

 quadrilateral (anterior border broadened out to a distinct fourth surface); 6 

 plano-convex; i = intermediary or indistinct. 



2 PP = pin point; sm = small; m = medium; I = large. When double or multi- 

 ple, state so. 



8 None ( ); rough trace - r. tr.', ridge: slight, medium, pronounced (r. sZ-m-pr); 

 tubercle: slight, or medium (ib. sl-m); process: 1/3, 1/2, 2/3, etc., complete (pr. 1/3, 

 1/2, 2/3, etc.). 



Notes. The length is taken on the osteometric board. Apply head 

 to the vertical, take hold of bone by left hand, apply block to distal 

 extremity, and raising bone slightly, move up and down as well 

 as from side to side until maximum length is determined. 



