In oviparous ("egg birth") sharks, a gland secretes a shell, or case, around the egg as it passes through the oviduct, protecting the shark until it hatches. The mother deposits the egg cases in the sea.
When the egg case is first laid, it is soft and pale; the case hardens and darkens in a few hours.
The egg case, when it is first laid is soft and pale.
The developing embryo receives nutrients from a yolk formed prior to fertilization.
A tiny shark embryo still attached to its yolk.
Oviparous sharks include horn sharks and swell sharks (Cephaloscyllium ventriosum).
Port Jackson sharks carry their egg cases in their mouths, possibly to drop them in a hiding spot. This is about the only shark parental care observed by humans.