PRINCIPAL REGIONS OF SPINAL CORD 95 



larly known as reflex animals. They stand close to the fox in 

 the small size of the dorsal funiculus as compared with the ventro- 

 lateral. It is probable that, in these animals, by far the greater 

 number of dorsal root axones terminate in the grey substance of 

 the cord after a comparatively short course in the dorsal funicu- 

 lus, thus accounting, in large part, for the small size of the latter. 

 Man and the monkeys, as examples of animals with a highly 

 developed encephalon, have relatively large dorsal funiculi; while 

 the fox, sheep, and rabbit with acute spinal reflexes have very 

 small dorsal funiculi. The relative size of the dorsal and ventro- 

 lateral funiculi, however, may be the result of many factors of 

 which we have considered but a few. 



This investigation has been carried on under the direction of 

 Prof. Irving Hardesty who kindly furnished much of the mate- 

 rial. I am under obligations to him for many helpful suggestions. 



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