Chimaeras resemble sharks in some ways : they employ claspers for internal fertilization of females and they lay sexual appendages on the forehead ( a type of tentaculum ) and in front of the pelvic fins.
42.
Male cartilaginous fishes ( sharks and rays ), as well as the males of some live-bearing ray finned fishes, have fins that have been modified to function as intromittent organs, reproductive appendages which allow internal fertilization.
43.
Internal fertilization with many vertebrates ( such as reptiles, some fish, and most birds ) occur via cloacal copulation ( see also hemipenis ), while mammals copulate vaginally, and many basal vertebrates reproduce sexually with external fertilization.
44.
During the last 6, 000 years, divergence in the larval development of " Cryptasterina hystera " and " Cryptasterina pentagona " has taken place, the former adopting internal fertilization and brooding and the latter remaining a broadcast spawner.
45.
Viviparous animals are similar to Ovoviviparous species in that there is internal fertilization and the young are born ( alive ), but differ in that there is no placental connection, and the unborn young are nourished by egg yolk.
46.
Ovoviviparous animals are similar to viviparous species in that there is internal fertilization and the young are born in an advanced state, but differ in that there is no placental connection and the unborn young are nourished by egg yolk.
47.
The most significant discovery about " Austroptyctodus " is that one specimen depicts a female pregnant with 3 unborn embryos inside her, showing that like " Materpiscis ", also from Gogo, this genus was a live bearer that reproduced through internal fertilization.
48.
After internal fertilization and the habit of laying eggs in terrestrial environments became a reproduction strategy amongst the amniote ancestors, the next major breakthrough appears to have been a gradual replacement of the gelatinous coating covering the amphibian egg with a fibrous shell membrane.
49.
Dawkins and Carlisle further expanded on this by suggesting that uniparental female care is dominant during internal fertilization because the male has time to desert, and uniparental male care is dominant during external fertilization because the male first waits for the female to deposit the eggs and only then does he fertilize them with his sperm, which gives the female time to escape.
