EXPERIMENTALLY PRODUCED EXTRAUTERINE PREGNANCY. 63 



A points to a central structure, which probably corresponds to 

 the Anlage of the neural tube. Under the abnormal conditions 

 under which the embryo must develop, the various embryonic 

 structures are evidently somewhat distorted. Fig. 3 shows the 



Fig. 3. The embryo proper, higher magnification, a, mitosis; c, surrounding 

 giant cells; d, a structure which perhaps corresponds to the placental cavities lined 

 with cuboidal cells. 



central part of the embryo at a higher magnification. A points 

 to the same cavity as a in Fig. 2. The cell designated by a is 

 seen in the process of mitotic division. Other embryonal cells 

 also divide mitotically at various places. Surrounding the central 

 parts of the embryo we find epithelial structures arranged in 

 layers adjoining as is shown on Fig. 2. Giant cells c surround the 

 embryo at various places on Fig. 3 in a similar way as seen on 

 Fig. 2. A larger number of giant cells are also found at a some- 

 what greater distance from the embryo. These giant cells are 

 arranged typically around cavities, which are lined by smaller 

 cuboidal cells. D on Fig. 2 points to such a cavity lined with such 

 cuboidal cells. Perhaps also the canal d on Fig. 3 corresponds to 

 such a cavity. The small cuboidal cells often proliferate and 



