define ovoviviparous and give example(s)reproduction in animals

Ovoviviparity is a reproductive system in which a female
animal produces eggs which are internally fertilized but are kept inside the mother's
body until they hatch, at which point the babies are
released.

To a casual observer this would look a lot like
viviparity, which is how mammals produce their young. However there are some important
anatomical and evolutionary differences. In viviparity the developing young are
typically encased in a placenta, and are getting nourishment from the mother's body. In
ovovivparity, the offspring are nourished by a yolk sac which is not connected to the
mother. However in both viviparity and ovoviviparity, oxygen and carbon dioxide are
exchanged between the offspring and the mother's body by
diffusion.

Most shark species are ovovivparous, as are some
bony fish such as guppies. A couple of really unusual examples would be the gastric
brooding frog Rheobatrachus silus, an Australian species in which
the female swallows her fertilized eggs and holds them in her stomach for more than a
month until the hatch, and seahorses, in which the female transfers her eggs into a
special brooding pouch on the male's belly, where they remain until they
hatch.