Reproduction in beings of the phylum Chordata is sexual, with the exception of urochordates that can also reproduce asexually. In some classes (cyclostomes, osteichthyes fishes and amphibians) there is larval stage. With rare exceptions, fishes, amphibians, reptiles and monotreme mammals are oviparous, egg laying (embryos develop within eggs and outside the mother’s body) and marsupial and placental mammals are viviparous (embryos develop inside the mother’s body, feeding from her).