408 FRANKLIN P. MALL 



The summary of these cases together with all others of the 

 same kind which I have been able to gather from the literature, is 

 given in table 1. This is an elaboration of the table given in 

 the Manual. The data are sufficiently complete so that those 

 who choose may look up the original records. Most of them, 

 however, will be found in abstract form in the articles by Triepel 

 and by Grosser.*^ The specimens in the Carnegie Collection 

 are recorded above. 



All of the specimens just given are entered upon figure 1. The 

 mean menstrual age and the mean copulation age are taken from 

 the data given in the table and in the curve published in the 

 Manual. For the specimens here considered the menstrual ages 

 are indicated by means of dots, the copulation ages by large 

 solid circles. The time is calculated by days, and the measure- 

 ments of the embryos are crown-rump. The numbers of several 

 specimens for which the copulation age is given are marked in 

 figure I; for instance, No. 443 and No. 1310. One of the Rabl 

 cases is also indicated. I am of the opinion that all these marked 

 records should really be excluded from the figure as they do not 

 appear to be very reliable. However, I have included them 

 for the sake of completion. Six of the copulation cases are 

 crossed in the figure with an X, and are given again in table 2. 



It will be noticed that these six records fall almost exactly 

 upon the curve given. They are, I believe, the only ones which 

 are entirely reliable; that is, they record embrj^os which are the 

 product of single copulations, and for this reason their maximum 

 ages are established. A word regarding specimen No. 26, which 

 is recorded in the literature as representing an embryo 30 mm. 

 long. As we are at present dealing with CR measurements, this 

 should be 25 mm. It appears on the chart in the Manual as 

 30 mm., for the reason that the curve was constructed on the 

 basis of the standing height, or CH length of the embryos. The 

 tables given by Triepel and by Grosser should, therefore, have 

 this measurement corrected accordingly. 



I have also entered upon my figure the ages of the embryos 



"Grosser, O. 1914 Alterbestimmung junger menschlichen Embryonen; 

 Ovulations und Menstruationstermin. Anat. Anz., Bd. 47. 



