INCTJBATORIAL AREA IN ECHIDNA 



31 



Stage 53, these formations, as originally de- 

 scribed by Gegenbaur, have grown much 

 larger than the sweat glands (Fig. 13b, dr). 

 I was able to examine the incubatorium of 

 Stage 53 in toto, and in Fig. 14, it will be seen 

 that the primary -primordia, now distinguishable 



Fig. 13b. — EcnmNA: Transverse Section through 

 THE Incubatorial Area OF Semon's Embryo, 

 Stage 53. 



Dr, Gland area ; sdr, sweat gland ; hm, skin-muscle. 



as the definitive gland areas, have just been 

 drawn into the region of the incubatorium, 

 but are still situated quite at the cranial corners 

 of the folds that surround it. Below in the 

 picture is the left gland area, a section of which, 

 still more highly magnified, is;shown in Fig. 13b. 

 It is therefore obvious that the gland areas 



