< II ART I. 



Chart 1. 



Growth curve based on crown-rump length and weight of embryos weighing less than 20 grams. 

 Each specimen measured with the body straightened out is entered as a dot ; those measured in their 

 natural curved posture are entered as crosses. The mean curves drawn through these two fields 

 overlap, showing that if embryos of 36 to 42 mm. are straightened out it adds about 4 or 5 mm. to 

 their length. Toward the bottom of the chart the foot length in millimeters is plotted according to 

 weight of embryo. A scale showing menstrual age, as in the succeeding charts, is placed at the top of 

 the chart. This scale is based on chart 6. 



Weiqht in qrams 



