ORGANS OF THE BODY. 



661 



The internal pillars, separated from one another by narrow clefts, all 

 spring up in the same line, external to the holes in the lidbenula per- 

 forata. They rest upon the membrana basilaris with a slightly expanded 

 base (n), which covers a mass of nucleated protoplasm. This is a remnant 

 of the original formative cell of the pillar. 



The upright portion of our internal pillar becomes, at first, somewhat 

 narrowed (down to 0-0034-0-0045 mm.), but terminates above in a 



v* 1 8-H|1S ) 



! 5-3.82-S-Sgs 



bs 



slf l?l~"l 



iMIfffif 





5 .S aj * ,-H 3 



ti 5 f*i!i 



B^aorf^SS*: 



sZsgSi'**! 



*.5'5'S'8fl."S 



bulbous swelling 0'0054 mm. in diameter (?n). Into a depression on the 

 outer aspect of the latter, the upper end or " head" of the external pillar 

 of Corti (o) (0-0079 mm. across) fits. 



This external pillar springs, with a similar expansion, from the mem- 

 brane upon which it rests, and presents here also the same nucleated 

 protoplasm as the internal. These protoplasmic cell-residues taken collec- 

 tively, are known as the " granular layer." 



