432 EDGAR H. NORRIS 



resents a reconstruction of a typical one of these large budding 

 follicles. Figure 7 is a graphic reconstruction of a number of 

 epitheUal masses found in the thyroid gland of the 60 mm. fetus 

 (No. 40) to demonstrate stages in the breaking up of the plates 

 and the formation of isolated follicles, which are present at this 

 time. 



The 65 mm. fetus (No. 41) is the first member of the series in 

 which practically no epithelial plates or bands are found. From 

 this stage on through the remainder of the series the thjo-oid 





Fig. 10 Microphotograph of a portion of a cross section of the thyroid gland 

 in a human fetus 86 mm. long (No. 44). Note the numerous branching follicles, 

 also the elongated follicles in various stages of division by constriction. This 

 section is in the region of the reconstruction shown in figure 15. X 100. 



gland is made up almost entirely of independent, soHd or hol- 

 low, more or less irregular epitheUal cell-masses. The stages 

 (Nos. 42 and 43) included between this embryo and the one of 

 86 mm. (No. 44) may be passed over briefly with the statement 

 that the processes of budding and formation of new follicles as 

 previously described are advancing rapidly parallel with the 

 increasing length of the fetus. 



The 86 mm. fetus (No. 44) deserves special attention for it 

 exhibits what appears to be the culmination of the budding proc- 

 esses referred to above. A study of figure 10 reveals the ex- 



