58 



FRANKLIN P. MALL 



1 gives the classified distribution of the first 1000 embryos in 

 the Carnegie Collection. The primary division comprises two 

 classes — pathological and normal. The pathological in turn is 

 arranged in the seven groups just described. The normal are 

 arranged in groups to correspond as nearly as possible with the 



7a 



7b 



Fig. 7 Croup 7, giving two specimens of fetus compressus. 7a, No. 996 

 from Dr. H. B. Titlow, Baltimore, X r. 7b, No. 868 from Dr. E. H. Egbert, Wash- 

 ington. X 2. 



ages of the embryos in lunar months. In order to define clearly 

 which embryos belong to a given month, I have inserted their 

 probable lengths for each month in table 6. Thus, for instance, 

 the second month includes all specimens from 2.6 mm. to 25 

 mm. in length, etc. (Data upon the estimated age of embryos 



