Cysts of Entamoeba histolytica/dispar.  Line drawing (G), wet mounts stained with iodine (H, I) and permanent preparations stained with trichrome (J, K).

 The cysts are usually spherical and often have a halo (H, I). 

 Mature cysts have 4 nuclei. The cyst in H appears uninucleate while in I, J and K 2 to 3 nuclei are visible in the focal plane (the fourth nucleus is coming into focus in J). 

 The nuclei have characteristically centrally located karyosomes, and fine, uniformly distributed peripheral chromatin. 

 The cysts in I, J and K contain chromatoid bodies with the one in J being particularly well demonstrated, with typically blunted ends.  Entamoeba histolytica cysts usually measure 12 to 15 µm

Courtesy of the Division of Parasitic Diseases at the National Center for Infectious Diseases, Centers for Disease Control and Prevension (public domain)

http://www.dpd.cdc.gov/DPDx/HTML/Amebiasis.htm