Histotrophy

Histotrophy is a form of matrotrophy exhibited by some live-bearing sharks and rays, in which the developing embryo receives additional nutrition from its mother in the form of uterine secretions, known as histotroph (or "uterine milk"). It is one of the three major modes of elasmobranch reproduction encompassed by "aplacental viviparity", and can be contrasted with yolk-sac viviparity (in which the embryo is solely sustained by yolk) and oophagy (in which the embryo feeds on ova).