1905.] Cord of the Macaque Monkey. 



(a) Grey Substance. (Chart V, Tables II and, VI) 



109 



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Lumbar Sacral* CoccyqeaL 



Chart V. — Curves showing the Mean Sectional Area (G, dotted line) and Percentage 

 Value [g, continuous line) of the Grey Substance in the Cross-section of the Cord 

 (Tables II, VI). 



The ordinates on the left-hand side of the chart denote section area in square milli- 

 metres, and on the right-hand side percentage value. The abscisste denote spinal nerve 

 regions. 



The sectional area of the white substance (W) increases from the first to 

 the fourth lumbar region, whilst the percentage value (w) decreases. 



Between the fourth and the seventh lumbar regions there is a decrease in 

 both. From the seventh lumbar to the third sacral region the sectional area 

 decreases, the percentage value remaining approximately the same. 



From the third sacral to the first coccygeal there is a decrease in both, and 

 from the first to the third coccygeal region the sectional area decreases, whilst 

 the percentage value increases. 



vol. lxxviii. — B. 



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