''Cirrothauma magna'', also known as the big-eye jellyhead, is a species of deep-sea cirrate octopus that has been found in the Indian, Atlantic, and Pacific oceans. It is known from four damaged specimens. The species was originally described in genus ''Cirroteuthis'', and was later allocated to ''Cirrothauma'' since its

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses Science Biology * Seashell, a hard outer layer of a marine ani ...

and elongate arms are similar to those of ''

Cirrothauma murrayi ''Cirrothauma murrayi'', the blind cirrate octopus, is a presumably blind octopus whose eyes can likely sense light, but not form images. It has been found worldwide, usually beneath the ocean's surface, but a single specimen was collected in the ...

''. More recently the species (along with ''I. hoylei'') has been allocated to a separate genus (''Inopinoteuthis'') given that these species differ rather strongly from ''Cirrothauma'' in having functional eyes (vs. vestigial eyes in ''C. murrayi'') and differ greatly in sucker form. ''Cirrothauma magna'' is likely the largest species of cirrate octopus, one female specimen measuring 1.7 m total length. The animal has delicate, jelly-like flesh.

References

Octopuses Molluscs of New Zealand Cephalopods described in 1885 Cephalopods of Oceania {{octopus-stub