PLATE 1 



EXPLANATION OF FICUKKS 



Figures photographed at natural size, reduced to one-half in reproduction. 



1 Cell 11 (table 2) at one micron. Thickness wax plate 2.56 mm., magni- 

 fication 2560 by Zeiss comp. oc. 18, homo, oil imm. 2 mm., tube length 140, stage 

 level. Number of layers for cell body 23, for nucleus 11. Area of layers in s.cm: 

 2.6; 5.5; 7.7; 10.1; 11.5; 16.7—1.1 (nucleus begins); 18.7—1.6; 21.5—1.6; 23.1—3.2; 

 18.3-3.5; 19.6—4.1; 16.4—2.6; 16.3—2.0; 16.8—1.9; 15.0—1.5; 14.5—1.2 (nucleus 

 ends); 13.5; 12.3; 9.3; 9.3; 7.2; 5.3; 2.9. In this cell the surface was smoothed down 

 after weighing. Note the atypical shape with a circular indentation. 



2 Cell 16, at one micron. From the same plate and magnification. Number 

 of layers for cell body 22, for nucleus 11. Area of layers in s. cm: 4.0; 9.0; 13.1; 

 16.4; 22.6; 28.9; 28.4; 28.8—0.9 (nucleus begins); 31.3—2.8; 29.2—3.3; 28.6—4.5; 

 27.6—5.1; 25.2—5.8; 24.0—5.0; 23.4—3.9; 21.0—2.7; 18.0;— 2.1; 16.4—0.9 (nucleus 

 ends); 15.2; 11.6; 9.3; 7.1. The cell was evidently sectioned obliquely. The 

 axone comes ofT from the side. As regards function, it represents a transition to 

 the first stage, and hence is considerably larger than its two regular mates in 

 table 2. 



3 Cell 12, at two micra. Thickness of wax plate 2.182, each layer being 

 reduplicated, magnification 2180 by Zeiss comp. oc. 12, homo, oil imm. 2 mm., 

 tube length 166. Number of layers for cell body 7, for nucleus 3, making a very 

 flattened cell in depth. Opened to show nuclear insertion. 



4 Cell 13, at two micra. From the same plate and magnification. Number 

 of layers for cell body 11 + 5, for nucleus 5 + 5. 



5 Cell 14, at two micra. Thickness of wax jilate 5.189, magnification per 

 micron 2595 by Zeiss comp. oc. 18, homo, oil imm. 2 mm., tube length 141. Number 

 of layers for cell body 9 + |, for nucleus 3 + w. 



500 



