Chapter 30 THE TRUE SHARKS

Order Notidani.-We may recognize as a distinct order, a primitive group of recent sharks, a group of forms finding its natural place somewhere between the Cladoselachid? and Heterodontid?, both of which groups long preceded it in geological time.

The name Notidani (Notidanus, νωτιδ?νο?, dry back, an old name of one of the genera) may be retained