Australia: The Land Where Time Began

A biography of the Australian continent 

Cosmine

Found only in the Sarcoptergii, this is a primitive tissue that is believed to have had the function of supporting a complex sensory system on the surface of the dermal bones.

It consisted of a layer of dentine above the dermal bone, containing flask-shaped cavities possibly containing sensory cells, connected to the outer surface by pores, connected by canals,  and probably formed a complex vascular system for the skin . The dentine layer was covered by an enameloid layer and the epithelium.

Sources & Further reading

John A Long The Rise of Fishes - 500 Million years of Evolution, University of New South Wales Press, 1995