Author Robert Hamilton (1794–1868)
English: Hammer-Headed Shark (1); Common Tope (2)
Subject: Sharks, Galeorhinus galeus
Tag: Fish
Date 1866
Source/Photographer
English: Hamilton, Robert (1866) British Fishes, Part II, Naturalist's Library, vol. 37, London: Chatto and Windus
Source: https://commons.wikimedia.org/wiki/File:FMIB_36391_Hammer-Headed_Shark_(1);_Common_Tope_(2).jpeg

The smooth hammerhead (Sphyrna zygaena) is a species of hammerhead shark, and part of the family Sphyrnidae. This species is named "smooth hammerhead" because of the distinctive shape of the head, which is flattened and laterally extended into a hammer shape (called the "cephalofoil"), without an indentation in the middle of the front margin (hence "smooth"). Unlike other hammerheads, this species prefers temperate waters and occurs worldwide at medium latitudes. In the summer, these sharks migrate towards the poles following cool water masses, sometimes forming schools numbering in the hundreds to thousands.

The school shark (Galeorhinus galeus) is a houndshark of the family Triakidae, and the only member of the genus Galeorhinus. Common names also include tope shark, soupfin shark, and snapper shark. It is found worldwide in temperate seas.