In a reverse hierarchy, the conceptual pyramid of authority is turned upside-down, so that the apex is at the bottom and the base is at the top. This model represents the idea that members of the higher rankings are responsible for the members of the lower rankings.
Along the sides of the body is a light-colored horizontal stripe called the lateral line. The line is made up of a series of tiny pores that lead to receptors that are sensitive to the mechanical movement of water and sudden changes of pressure.The spiny dogfish has a double dorsal fin.The anterior dorsal fin is larger than the posterior dorsal fin.The spiny dogfish has the presence two spines, one immediately in front of each dorsal fin. The spines carry a poison secreted by glands at their base.he spiny dogfish has a double dorsal fin. The anterior dorsal fin is larger than the posterior dorsal fin. The spiny dogfish has the presence two spines, one immediately in front of each dorsal fin. The spines carry a poison secreted by glands at their base.
The eyes of this species are quite large. The first dorsal fin is located about halfway between the pectoral fins and the pelvic fins. The second dorsal fin is about two-thirds the size of the first one and is located behind the pelvic fins.On the front of each dorsal fin there is a sharp spine attatched to them, giving the Spiny dogfish its name. The first spine is about half as long as the second spine.here is no anal fin on the Spiny dogfish. The dorsal surface of the Spiny dogfish is slate-coloured and may have a brownish cast. There are rows of white spots along each side, from above the pectoral fins to above the pelvic fins.