[Summary]
Day of Hunt during a Winter tide at Saint-Malo, N. Brittany.
Variations in Calliostoma zizyphinum (Linnaeus, 1758).
 
At a few hundred meters from Bon Secours beach and its tide pool, the two islets of Grand & Petit Bé host many rock-living species. During the tide of feb.18th, the sea was so far offshore that many surrounding reefs that are usually underwater came to surface. I had then the possibility to sample various specimens of Calliostomas that live at depths of 4-6m under average low tide level. Among them, the pale form lyonsi.
 
From purple to pale
 
These Topshells fade progressively while depth increases, but I am not sure it is a general law.
For each specimen pictured at left, the right column shows the predominant species that are found in the close neighbourhood (1m around the Callio). Click on each picture to load larger views.
 
 
24mm
   Infralittoral, among red algae (Sphaerococcus), in rocks.
 
24mm
   Under red algae, on sea-wall along the Petit Bé.
 
23mm
   Under red algae, on sea-wall, 1m upon low tide level.
 
22mm
   On flank of sea-wall, 50cm upon low tide level, in crevice.
 
22mm
   Under stones covered with yellow microalgae, low tide level.
 
21mm
   Under stones, with yellow microalgae, low tide level.
 
21mm
   In crevice, 30cm under low tide level, end of causeway (jetty).
 
19mm
   Offshore, in wide ripple-marks, sand-gravel bottom, 50cm deep.
 
Bonus
 
Beside this promenade in company of Callios, Painted or not, many other species ask for a bit of representation in these page. Apart Scissor-clams and Cockles, which were rudely pursued with blows from picks and shovels, I noticed a large number of other species that were ignored by beachcombers.
Sheltered in hollows among large ripple-marks, crawling or hopping from dune to dune at the foot of the city walls, here they come: (each thumbnail is clickable).
 
[Summary]