Linked from
The 17 pages that link to Internal fertilization, each with the reason it gives.
ChondrichthyesRelated: Male chondrichthyans use claspers to transfer sperm during mating.
ReptiliaRelated: It allows reproduction without releasing gametes into water.
GuppyRelated: Male guppies transfer sperm with a modified anal fin called a gonopodium.
CopulationRelated: Copulation often enables sperm to reach eggs within the reproductive tract.
CyprinodontiformesRelated: It occurs in the livebearing lineages of Cyprinodontiformes.
MatingRelated: Many mating systems transfer sperm into a partner before fertilization.