140 



Journal of Comparative Neurology. 



In addition to the occurence of the fascicuH cerebro-spinales 

 interni and the resulting pecuUar position of the canahs cen- 

 traHs, further macroscopic examination of the sections will prove 

 that in the thoracic segments, the nucleus dorsalis (Clarke's 

 column) possesses features considerably different from what ap- 

 pears in the meduUae spinales of the mammals usually studied. 

 The position of the nucleus in the cervix of the columna pos- 

 terior is exceedingly well defined in the more cephalad thoracic 

 segments (Figs. lo, ii, 13, 14, 15), and it increases in size 

 in passing from thoracic VIII to thoracic II. A microscopic 

 study of the nucleus is deferred to another section of this paper. 



For purposes of comparison and in order to present a 

 more detailed quantitative study of the relative proportions of 

 substantia grisea and substantia alba in the different levels, a 

 series of measurements were made of the various dimensions of 

 each section according to the scheme represented in text-figure 

 I. The results of these measurements are recorded in Table IL 

 The number enclosed with the title of each entry in the table cor- 

 responds to the dimension indicated by the like number in text- 

 figure I. These measurements were suggested by similar meas- 



Texl-fixwr j — Showing the scheme according to which measurements were 

 made of the various dimensions of the transverse sections of the medulla spi- 

 nalis of the elephant. The lines in the figure indicate the extent and direction 

 of each measurement and the numbers of the lines correspond to like numbers 

 enclosed in the entries in Table II in which the measarements are recorded for 

 the different sections involved. 



urements made by Kopsch, and the scheme is intentionally the 



