Ontogeny

Ontogeny
Ontogeny: development of an individual from the moment the egg is fertilized up till adulthood.
Opaque area: non-transparent part.
Pellucid area: transparent part.
Neural fold: fold related to the head.
Neural tube: extension related to the head.
Heart: blood-pumping organ.
Somites: metameres.
Omphalomesenteric arteries: vitelline duct.
Wing buds: beginning of the formation of the wings.
Limb buds: beginning of the formation of the legs.

Photo :

EN : Feet of ostrich
FR : Pieds d'autruche
ES : Pies de avestruz

Feet 
          of ostrich

Its feet of ostrich are very curious, and different from those of all other birds. They are somewhat like the foot of the camel, having a soft pad or cushion underneath, and only two toes. The largest toe is about seven inches long, and has a broad claw at the end; the other is about four inches long, and has no claw. Although ostrich cannot fly, it can run faster than the swiftest horse.

Animation : Bird's eggs


Thanks to YouTube for allowing us to watch this video.