The elastic system in the thymus of the opossum Didelphis marsupialis aurita.

The author studied the elastic system of fibers in the thymus of the opossum. 2 types of fibers were found: elastic and oxytalan. The elastic fibers form a dense network at the periphery of thymic capsule, while a delicate meshwork of oxytalan fibers is found at the inner part of the capsule, being connected to the elastic plexus by some elastic fibers which cross the whole thickness of the capsule. Within thymic trabeculae only oxytalan fibers were observed. The peculiar arrangement of the elastic system of the thymus perhaps allows the organ to be exposed to mechanical shocks without transmitting such stress to the thymic parenchyma.