92 Miss M. P. FitzGerald. The Lumbosacral-coccygeal [June 17, 



The number of nerve roots in the spinal cord of the Macaque monkey is 

 as follows: 7 cervical, 12 dorsal, 7 lumbar, 4 sacral and 3 coccygeal. 



The portion of the cord from which each pair of nerves arise has been 

 spoken of throughout this paper as the corresponding " region." 



The particular portion of the cord examined extended from the upper 

 limit of the region of the first lumbar nerve to the lower limit of the third 

 coccygeal region and measured approximately 6 - 3 cm. 



In the charts dealing with section areas and with percentages (Charts I to 

 IV and XIII, XIV), the length of the cord is expressed along the abscissa 

 line in centimetres and parts of a centimetre. The uppermost section of the 

 first lumbar region is taken as zero. The distance from zero to each 

 measured section is given in centimetres or parts of a centimetre in a 

 separate column in each table of figures (except in those where only mean 

 results are quoted), and on the curves the observation points are marked by a 

 dot or cross as nearly as possible in the exact position indicated in the table. 



As a matter of convenience, the first drawing made in the first lumbar 

 region was of a section occurring at - 142 cm. below that taken as zero. 



In the section area and percentage charts which give the complete results 

 obtained (Charts I to IV and XIII, XIV), the numbers I, II, III, IV, etc., 

 mark on the zero abscissa line the approximate cephalic end of the region of 

 each pair of spinal nerves. 



In the charts where the curves are constructed from mean figures 

 (Charts V to XII, and XV to XX), the length of the cord and of the 

 individual nerve regions has been disregarded, and the calculations referring 

 to the region of each nerve (marked I, II, III, etc.) are plotted at equal 

 distances along the abscissa. 



The paper is arranged in the following order : — 

 A 1. Areas of the cross-sections of the spinal cord and of the grey and of 

 the white substance in the region of each spinal nerve. 



2. Percentage of the grey and of the white substance in the cross- 



section of the cord. 



3. Eatio of the total white substance, and of the dorsal and of the 



ventro-lateral white columns, to the grey substance. 



4. Eatio of the dorsal and of the ventro-lateral white columns to the total 



white substance. 



5. Eatio of the ventro-lateral to the dorsal columns. 



B 1. Section areas of the dorsal and of the ventral horns of the grey 

 substance. 



2. Percentage of the dorsal and of the ventral horns in the total grey 

 substance. 



