Egg cases are made of collagen protein strands, and are often described as feeling rough and leathery. Some egg cases have a fibrous material covering the outside of the egg case, thought to aid in attachment to substrate. Egg cases … 展开

The skates (Rajidae, Arhynchobatidae, Anacanthobatidae) are the only rays that are oviparous. Females lay egg cases onto the sea floor after … 展开

The egg case genera Palaeoxyris and Fayolia, which are thought to have been produced by hybodonts and xenacanths respectively, two groups of extinct shark-like cartilaginous fish more closely related to modern sharks and rays than to chimaeras, resemble … 展开

Shortly after internal fertilization, the fertilized ovum enters the partially formed egg case located in the oviduct. After the ovum enters, the rest of the egg case forms around it. Shortly after the egg case finishes developing, it is deposited outside the body; common … 展开

Oviparity in sharks can be categorized as single or retained. With single oviparity, the egg cases are extruded soon after fertilization. With retained … 展开

All known chimaeras produce egg cases. The egg cases of chimaeras are spindle- or bottle-shaped with fins on the sides. They are laid on the … 展开

Predation on egg cases is thought to be a major source of mortality for developing oviparous sharks, skates and chimaeras. In general, predation is the leading cause of mortality for marine fish … 展开