Egg‐jelly production and composition in an oviparous chondrichthyan, Scyliorhinus canicula (Linnaeus, 1758).

Embryos of oviparous chondrichthyans develop within a structurally complex tertiary egg envelope known as the egg‐case, which is provisioned with a secondary egg coat known as the egg‐jelly. Whereas the former has been studied in detail, relatively little attention has been paid to the latter. This study examined the production and composition of egg‐jelly in the small‐spotted catshark Scyliorhinus canicula (Linnaeus, 1758) and determined that it is a mucin hydrogel. The role of the egg‐jelly appears to be one of simple, physical support for the developing embryo, as it was not found to possess bactericidal properties, nor did its constituents suggest a nutritive role. [ABSTRACT FROM AUTHOR]