150 



THE HUMAN EMBRYO. 



is larger, and has risen so as to be about at right angles to the body. The con- 

 cavity (Nackengrube) below the hind-brain in the outline of the neck is more 

 marked. The limbs are longer, the fingers more distinct. Where the mandibles 

 meet in the median line, the separation of lip and chin has begun. 



Embryos of Thirty-six Days, 14 mm. The correlation of age and size for this 

 stage cannot be recorded as absolute, but we may say that embryos of this length 



FIG. 99. HUMAN EMBRYO OF ro.o MM. WITH THE AMNION, CHORION, AND YOLK-SAC. SERIES 1000. X 5 diams. 



(Compare Fig. 100.) 



are about five weeks old. The body is now nearly straight (Fig. 102). The 

 lower limbs project beyond the outline of the body in profile views. The bulging 

 of the outline at the neck-bend is characteristic of this stage, but in the specimen 

 figured the protuberance is unusually great. The ventral outline, owing to the large 

 size of the heart and liver, is very protuberant, and at this stage we find that the 

 portion of the umbilical cord adjoining the embryo is greatly enlarged, owing to the 

 distention of its coelom, so that a large cavity is furnished in which there are al- 

 ways found, as indicated in figure 84, several coils of intestine. This protrusion of 

 a portion of the intestinal canal, and sometimes even of a small portion of the 



