Matryoshka abalones

These colourful shells are abalones, edible sea snails, otherwise known as ear-shells, sea ears, muttonfish, venus's-ears, paua, or, in Great Britain, ormers. The holes in the shell are vents out of which sea-water is forced after flowing over the gills during breathing. 

The largest shell is from Guernsey, the smaller ones from the Fijis.