1. An extensive network of lymphatic vessels coming from the thymus of the guinea pig and carrying thymocytes to the general circulation has been demonstrated.
2. Local accumulations or infiltrations of cells at the surface of the lobule or in the interlobular septa have been observed through which thymocytes appear to leave the thymus.
3. Irregular, tortuous canaliculi, resembling a lymph sinus in a lymph node, seem to play an important role in transporting thymocytes from these accumulations to the typical lymphatic vessels.
4. The output of thymocytes via lymphatic vessels to the general circulation is about 12.1 x 106 per day.