Chart fi. 



Crown-rump length 



70 SO 90 100 



120 I JO 



200 210 



270 200 



Field and curve of mean menstrual age for specimens in the Carnegie Collection having menstrual 

 histories. The circles placed at the 32d, 36th, and 40th weeks are taken from Zangemeister's (1911) 

 data and arc used to complete the curve to the termination of pregnancy. 



