George L. Streeter 143 
by a difference in the thickness of the opposite edges, and the degree of 
obliteration of the line of juncture. The remainder of the vesicle wall 
is everywhere quite uniform in appearance, consisting of 2-3 layers of 
slightly elongated epithelial cells, without any apparent differentiation to 
indicate points of future nerve endings. 
ac. endolympn. 
ECOCMIEa 
mea. aud. ext. 
motor VI. 
\_ chora. tymp. 
\ 
\ 
\ 
petros. sup. maj. 
Fig. 1. Profile reconstruction showing the membranous labyrinth and its 
relative size and relations to the brain and the fifth and seventh cranial 
nerves. Human embryo 14 mm. long, Mall Collection No. 144, magnified about 
8 diams. 
No epidermal stalk could be detected connecting the vesicle with the 
surface, or persisting beneath the surface epithelium, as observed in the 
rabbit by Krause, 03, p. 88. Evidently in the human embryo such a 
stalk must be either very temporary or else never present, as here we 
have to do with a vesicle whose closure and detachment from the surface 
must be regarded as only just completed. 
