This ovigerous mass was 4 meters deep, on a soft seabed but also near hard seabed, probably produced by a gastropod mollusk, can anyone tell me if there is an atlas of the eggsmass of the gastropods?
It seems to be an egg mass of mollusks of the Family Naticidae. I recommend you to check the marine life photography websites from the Region you saw this. By the way, where did you take the picture?