Matrotrophy associated with vertebrates and especially mammals, matrotrophy is found in 21 of 34 animal phyla, and is fairly common in 11 of those. It has arisen independently in more than 150 clades within Chordata and in more than 140 clades amongst invertebrates. Matrotrophy Matrotrophy is a form of maternal care during embryo development. Some flowering plants supplied the developing embryos for the first stages. The ovule has no stocks and the nutrients are provided by the "mother". In plants, matrotrophy is considered a critical evolutionary development preceding the origin of embryophytes and therefore essential to the evolution of land plants.
Nephridium In freshwater crustacea, the saccate metanephridia are especially large because they are involved in osmoregulation. They have to remove large amounts of water from the tissues, as the crustacean's tissues are hypertonic to the surrounding water. A protonephridium ("proto" = "first") is a network of dead-end tubules lacking internal openings found in the phyla Platyhelminthes, Nemertea, Rotifera and Chordata (lancelets). The ends are called "flame cells" (if ciliated) or "solenocytes" (if flagellated); they function in osmoregulation and ionoregulation, respectively. The terminal cells are located at the blind end of the protonephridium. Each cell has one or more cilia and their