When seminude subjects were exposed to heat, the onset of cutaneous vasodilatation occurred simultaneously in the calf, forearm, cheek and ear. Progress of vasodilatation in the calf and toe often differ d from that in the forearm, cheek and ear. Vasodilatation in the calf was either small or stabilized early while the forearm vessels continued to dilate markedly. One subject, a poor sweater with unusually high skin temperatures, repeatedly presented an e ception in that vasodilatation in the calf exceeded that in the forearm. The usual failure of skin temperature to rise as much in the calf as in the forearm appeared to be related to the lesser cutaneous vasodilatation. There was no evidence that local sweating elicited local vasodilatation. (Author).