Mantle short, cup-like. Fins in adults extending beyond mantle end. Arms in larvae as long as mantle, in adults 1.5-3 longer. Inner arm web in juveniles a third, in adults 50-60% of arm length, outer web poorly developed. Arm suckers rather small in juveniles, globular, with low, barely noticeable teeth. Tentacles very long. Club suckers in 5-6 rows, equal in larvae but in adults median suckers in 2 central rows much larger than others. Buccal membrane with 6 lappets, connectives to 4th arms attached to dorsal parts of 4th arms and to middle of web joining 3rd and 4th arms.
Large ventral mantle photophores distributed in 7-8 diagonal rows, each with 7 photophores, gradually diminishing posteriorly; 4-5 photophores along midline of ventral head surface; 3 longitudinal rows at the base of all arms; one long dark photophore on ends of 1st-3rd arms, short one on 4th arms; 17 large photophores around right eye; an arch of 7 large photophores anterior to, and approx. 10 small ones lateral and posterior to left eye; 3 conspicuous large round black photophores posterior to left eye on ventral side of head. Skin not papillate.
Larvae with large eyes, relatively short arms, globular arm suckers, and thick tentacles. Mantle photophores are developed at ML approx. 5 mm, arm end photophores on 1st-3rd arms at 7 mm; larvae covered with many large chromatophores. Six-lappet buccal membrane and arm-end photophores are particularly characteristic. Egg size 2.3 mm. ML up to 33 cm.
Histioteuthis bonnellii is distributed in the Atlantic from SW Greenland and Iceland to the Southern Subtropical Convergence, including the Mediterranean, but not the Gulf of Mexico, Caribbean Sea and both Central Water Masses. Also present in the southern subtropical and temperate belt (20-30° to 40-45°S) of the S Indian and SW Pacific Ocean.