Histioteuthis is a genus of squid in the family Histioteuthidae. It goes by the common name cock-eyed squid, because in all species the right eye is normal-sized, round, blue and sunken; whereas the left eye is at least twice the diameter of the right eye, tubular, yellow-green, faces upward, and bulges out of the head.
In 2017, researchers at Duke University established that Histioteuthis uses its larger eye to see ambient sunlight, and its smaller eye to detect bioluminescence from prey animals.[1]
The name is composed of the Greek (Greek, Ancient (to 1453);: [[wikt:ιστίο|ἱστίον]], "sail", a large webbed membrane between six of the arms, in some species) and ("squid").[2] [3]
The genus contains bioluminescent species.[4]
. Agnes Catlow. Popular Conchology. 1854. Longman. 364. Histioteuthis, sail, and cuttlefish.
. Carl Chun . The Cephalopoda. 1975. Israel Program for Scientific Translations. 978-0-7065-1259-5. 120. Histioteuthis is characterized by such a large membrane ("sail") [...] This "sail" is a strong, muscular cutaneous membrane which surrounds the 1st, 2nd and 3rd arms.