Starfish and conches have eyes at the end of their tentacles. the arrowhead crab's eyes on each side of its head allow it to see very far around as well asdirectly in front. the hammerhead shark's eyes are at the end of large lobes on the head, so the shark is not able to see straight ahead. with its eyes on theunderside of its head, the bittern must tilt its head all the way up to see straight ahead. since it makes its nest in marshes, it may only need to survey thelandscape below its head.