In rats and guinea pigs one testis was removed from the scrotum into the abdomen, and the opposite testis to a position between the body wall and skin, the blood and nerve supply and ductus deferens connection being kept normal. Some months after operation the subcutaneous testes were carrying on spermatogenesis although spermatozoa were never produced. In contrast, the abdominal testes were practically devoid of all germinal epithelium. These findings are interpreted as follows: Since it has been earlier shown by the author that the lower temperature in the scrotum (than in the abdomen) is necessary for complete spermatogenesis, it would appear that in the subcutaneous position the skin affords reduction of temperature as compared with that in the interior of the abdomen, though not sufficient to allow complete spermatogenesis.