Radiographie d'un coquillage marin. Image noir et blanc. Tags: coquillage; coquille; spirale; radiographie; rayons X; transparence; hélice; hélicoïdal; fond noir; radiograph; X rays; ray; transparency; spiral; shell; helix; helicoid; black; background; monochromic; simple; natural; sharp; defined; regular; Nature; fragile; conical; winding; increasing; decreasing; delicate;