1892.] the Posterior Roots of some Spinal Nerves. 



337 



muscles of the foot, but its skin-field is on the buttock. In the lower 

 half of the trunk and in the pelvic limb the skin at any point will be 

 supplied bj sensory spinal roots segmentally anterior to (higher than) 

 the spinal motor root supplying the subjacent muscle. A partial ex- 

 ception to this will be in the skin of the back of the thigh, where, for 

 reasons explained, the supply of both may be from the same segmental 

 level. 



The cutaneous fields of the posterior spinal roots do not correspond 

 with the fields of cutaneous distribution of the motor roots, as judged 

 by the pilomotor fibres of those roots. The pilomotor fields and the 

 cutaneous sensory fields do not correspond. 



As to cutaneous vasomotor fields and the cutaneous sensory fields, 

 there does in Macacus rhesus seem to be a curious correspondence of 

 the area of " sexual " skin at the root of the tail, on the buttock, and 

 along the back of the thigh with the combined sensory skin field of 

 10th, 9th, and 8th post-thoracic roots. 



'tail. 



Tht mvd-doraai or 

 the. mid- vervtrcU- 

 line, of the trunk 



.place, uhere. the, ntid^oiorsal or mid-ventral 

 ' lute, fold* laterally ino the. Linib. 



Cutaneous Segments of the Pelvic Limb of Monkey, dorsal or ventral aspect. 

 (The overlapping of the segments is not shown.) 



