1905.] 



Cord of the Macaque Monkey. 



Ill 



The sectional area of the dorsal columns (P) increases from the first to the 

 fourth lumbar region, the percentage value (p) at the same time decreases. 

 From the fourth to the first sacral region there is a decrease in both ; the 

 sectional area continues to decrease from the first to the third sacral, whilst 

 the percentage value increases slightly. From the third sacral to the third 

 coccygeal region there is a decrease in both. 



(d) Ventro- Lateral Columns. {Chart VIII, Tables V and VII.) 

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 Sacred, Coccygeal 



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Chart VIII. — Curves showing the Mean Sectional Area (A, line and dot) and the Mean 

 Percentage Value (a, continuous line) of the Ventro-lateral Columns in the Cross- 

 section of the Cord (Tables V, VII). 



For the section area in square millimetres the value of the ordinates is given on the left- 

 hand side of the chart, and for the percentage on the right-hand side. The abscissae 

 denote the spinal nerve regions. 



The sectional area of the ventro-lateral columns (A) increases from the first 

 to the fourth lumbar region, whereas the percentage value («) decreases. 



From the fourth to the seventh lumbar there is a decrease in both. From 

 the seventh lumbar to the first sacral the sectional area decreases and the 

 percentage value increases. 



From the second sacral to the first coccygeal region there is a decrease in 

 both, and while the sectional area continues to decrease from the first to the 

 third coccygeal region the percentage value increases, and to the greatest 

 extent in the third coccygeal region. 



