DEVELOPMENT OF THE NUCLEI PONTUS IN MAN 



embryonic corpus ponto-bulbare. He believes that the adult 

 structure may contain portions of undeveloped embryonic tissue 

 and be responsible for the frequent tumors in the cerebello-pon- 

 tine angle. With the exception of the mention made by His 

 of a migration of cells to form the arcuate nuclei nothing has 

 been contributed to their development. 



TABLE 1 



In carrying out this investigation the writer was given abundant 

 opportunity to examine the large collection of human embryos 

 brought together in this laboratory by Professor Mall. Table 

 1 gives a list of the embryos used in this study. 



Wax plate reconstructions were made after the method of Born. 

 Human, pig and rabbit embryos, stained in toto with alum- 

 cochineal, were prepared for dissection as described by Streeter 

 ('04, p. 87). Whole brains stained in iron-haematoxylin also 

 gave brilliant differentiation. The most instructive specimens of 



