Abstract
Stingrays of Myliobatiformes Order are considered histotrophic viviparous, due to the fact that embryos are nurtured by secretion of villiform mucous produced by the mother uterus, known as trophonema, which is rich in lipids ("uterine milk") and proteins of high molecular weight. It is well known and studied that, during the reproductive cycle of fish, under the hormone regulation of the…