GEORGE L. STREETER 



adult, which is taken from Schonemann's reconstruction^ and 

 reprotlucecl here so as to be on the same scale of enlargement as 

 the younger stages. Since the cartilaginous labyrinth cor- 

 responds closely in form to the membranous labyrinth, particu- 



20 mm 



30 mm. 



50mmr 



Fig. 1 Median views of wax-plate models of the left membranous labyrinth 

 in human embryos having crown-rump lengths as indicated in the figure. The 

 largest one is taken from Schonemann ('04) and represents the adult condition. 

 They are all on the same scale of enlargement (4.4 diameters) and thus compari- 

 son of them shows graphically the amount of growth the labyrinth experiences 

 during this period. 



larly as regards the canals, one can see from figure 1 that there 

 is a progressive increase in the size of the cartilaginous chambers 

 throughout the whole embryonic period. 



In addition to this increase in size, there is a change in the 

 form of the cartilaginous labyrinth. The general proportions 



1 Schoenemann, A. Die Topographic des menschlichen Gehororganes. Ver- 

 lag von Bergmann, Wiesbaden, 1904. Plate 2, figure 20. 



