Oviparous is an objectionable term applied to the great majority of female animals, whose eggs are first laid and then hatched. Oviviparous is a corresponding term applied to animals in which the eggs are hatched within the body of the mother, and where there is no nutritive connection between parent and offspring. Some reptiles, amphibians, fishes, &c. which do not lay their eggs illustrate this mode of parturition. In regard to the terms oviparous and ovoviparous it should be noted (1) that all animals are in one sense viviparous, for whatever is born is normally alive; (2) that 'viviparous' animals par excellence—viz. the placental mammals—differ from 'ovoviparous' animals, such as the brown lizard (Zootoca vivipara), the blindworm, the black salamander (Salamandra atra), one of the blennies (Zoarces viviparus), and many invertebrates which bring forth already hatched young, not so much in the manner of birth as in the relation between mother and offspring before birth; (3) that oviparous and viviparous parturition often occur in the same class—witness the oviparous Monotremes among mammals; (4) that oviparous and ovoviparous parturition often occur in nearly related forms among reptiles, fishes, amphibians, and invertebrates—that they even occur in the same animal: e.g. the grass-snake (Tropidonotus natrix), which usually lays eggs, but may in artificial conditions bear already hatched young; or some aphides in which the parthenogenetic generations are usually born as young insects, while the fertilised eggs are laid as such. In short, the distinctions are for the most part differences of degree.
• Ovoca. See AVOCA.