from The Century Dictionary and Cyclopedia
- n. A genus of parasitic suctorial crustaceans, of the group called Epizoa, or fish-lice, having the elongated labium and metastoma united in a tube which incloses the sharp styliform mandibles, typical of the family Caligidæ. C. curtus is a parasite of the cod.
Sorry, no etymologies found.
I’d recommend caligus, fog, if you insist on atmospheric phenomena; but velo, velare conveys your meaning without assistance.