Columbia subject headings:
Fertilization (Biology)
Gametogenesis.
Ultrastructure (Biology)
Vertebrates--Embryology.
Harvard subject headings:
Fertilization (Biology)
Gametogenesis.
Germ cells--Ultrastructure.
Vertebrates--Embryology
Princeton subject headings:
Embryology--Vertebrates.
Fertilization (Biology)
Gametogenesis.
Ultrastructure (Biology)