The gastric peduncle dangles inside the bell, and the mouth at the tip of the small manubrium has four simple lips.

[2][3] Aglantha digitale is the most common species of jellyfish found in surface waters in the Arctic and sub-Arctic.

[2] Aglantha digitale is unique among known jellyfish[4] in having giant axons in the subumbrella (the concave inner surface of the bell) which are involved in a rapid escape response.

[5] Normally the hydrozoan swims by slowly pulsating its bell, movements produced by muscle contractions which eject water through the velar opening.

[4] In its pelagic habitat, this hydrozoan finds itself among relatively fast moving crustaceans, fish larvae and arrow worms in a jostling diurnal vertical migration, and the escape response may help it to avoid damage to its fragile tissues.