In some sharks, spiracles are present as first gill slits. These slits are located behind the eyes, and they are used to send blood through a separate, unique blood vessel immediately to the eyes and brain of the shark.
Electrosensory – Sharks have a bioelectrical system used to detect prey and navigate by the ocean’s magnetic fields. All sharks have tiny “jelly-filled canals located over the snout, that are able to detect and process electrical currents at short ranges. It is thought that sharks evolved its head in order to increase the surface area of its electrical receptors or perhaps the distance between sensors aids in determining direction of prey.
This photo show the spiracle