Sevengill Shark: Notorynchus cepedianus
- Biological profile of this species with photographs and information on its taxonomy, distribution, distinctive features, reproduction, interaction with humans and status.
- http://www.flmnh.ufl.edu/fish/Gallery/Descript/Sevengill/Sevengill.html

Bigeye Sixgill Shark
- Biological profile of Hexanchus nakamurai with photographs and information on its taxonomy, distribution, distinctive features, reproduction, interaction with humans and status.
- http://www.flmnh.ufl.edu/fish/Gallery/Descript/BigeyeSGill/BigeyeSgill.html

Hexanchiformes
- Information from Wikipedia on this primitive order of sharks, members of which include the cow sharks and the snake-like frilled shark.
- http://en.wikipedia.org/wiki/Hexanchiformes