Mantle conical, rounded behind, semigelatinous. Head fused with mantle, poorly separated from body and arms. Eyes very large, diameter up to 40% ML, open (not covered by corneal membrane). Mantle opening moderately wide, reaching midpoint between eye and funnel. Funnel sunken into head tissues almost to its opening. Mantle locking-apparatus lacking. Pair of long paddle-shaped fins without cartilaginous base on sides of posterior part of mantle. In smallest larvae larval fins on very end of mantle. At ML approx. 9 mm, pair of definitive fins beginning to develop anterior to larval one, at ML 20-25 mm larva with two pairs of fins of subequal length, then definitive fins grow more rapidly and at ML approx. 30 mm larval fins gradually resorbed. Arms short, subequal, twice as long as mantle, with tapering ends. Web deep, approx. half of arm length. Suckers small, unstalked, without horny rings, in one row, beginning far from mouth, approx. halfway between it and web margin, thread-like arm ends naked. Along both sides of each arm two rows of cirri, one pair near each sucker, beginning closer to mouth than first suckers and extending almost to arm ends. Between 1st and 2nd arms pair of thin retractile suckerless filaments usually coiled inside of special pouches on outer side of web. Tentacles absent. Two large complex evertible photophores located on dorsal mantle side between bases of definitive fins and rudiments of larval ones (present in larvae ML 6-7 mm), and very many small photophores dispersed on arms, head, ventral mantle and fins. Two large light oval spots, supposedly extraocular photoreceptors on head between eyes (present in larvae ML >10 mm). Radula present, all teeth unicuspid. No ink sac. Gladius very thin, wide, transparent. Body exterior dark purple-violet, arms and web inside intensely velvet-black. Color not variable (chromatophores are nonfunctional). Egg size 3.8 mm. ML up to 13 cm. Larvae are almost adult-like except fins.