Species in the family are entirely pelagic and have a very fragile, gelatinous structure and eyes that vary from large to small to degenerate. They are usually found in association with the ocean floor (benthopelagic) at great depths. Some have, however, been caught far above the bottom and one specimen was dip-netted through an ice hole in the Arctic.

Brief diagnosis:

A cirrate ...

• with long cirri and secondary webs.
• with saddle-shaped shell.
• with anterior mantle attached dorsally to head.