The parasitised red blood cell is up to twice as large as a normal red cell and Schüffner's dots (also known as Schüffner's stippling or Schüffner's granules) are seen on the infected cell's surface. Schüffner's dots have a spotted appearance, varying in color from light pink, to red, to red-yellow, as coloured with Romanovsky stains. The parasite within it is often wildly irregular in shape (described as "amoeboid"). of "P. vivax" have up to twenty merozoites within them. It is rare to see cells with more than one parasite within them. Merozoites will only attach to immature blood cell (reticulocytes) and therefore it is unusual to see more than 3% of all circulating erythrocytes parasitised.