The testis is the singular form of testes. The rabbit testes are much like that of any other mammal. In fetal development they are formed early in the abdomen and generate testosterone which causes the external genitalia to develop in the male formation. This also influences the nervous system and certain other parts of the body. Later, they drop down into the scrotum (in most mammals) and continue to generate testosterone which is responsible for most secondary sexual characteristics. At puberty the production of testosterone is increased and the testicles also begin producting spermatazoans.

This slide was purchased on Ebay and is part of 100 prepared slides " set B"