Representative images of host species and parasites for which rRNA sequences were obtained. Bars, 50 μm. (A) Eutintinnus pectinis lorica filled with sporocytes of Euduboscquella cachoni. (B) Lorica of Eutintinnus tenuis containing Euduboscquella cachoni in early sporogenesis. (C) Favella arcuata lorica, with sporocytes of Euduboscquella sp. located below host cell (H). (D) Favella panamensis from Assawoman Bay, MD, with host cell (H) positioned above sporocytes of Euduboscquella crenulata. (E) Lorica of F. panamensis from Indian River Lagoon, FL, housing sporocytes of Euduboscquella cf. crenulata. (F) Favella panamensis lorica from Solomons Island, MD, with Euduboscquella cf. crenulata in a second sporogenic division. (G) Host cell (H) and sporocytes of Euduboscquella cf. crenulata in F. panamensis lorica from York River, MD. (H) F. panamensis from Masan Bay, Republic of Korea, with numerous sporocytes of Euduboscquella cf. crenulata posterior to host cell (H). (I) Lorica of Favella markusovszkyi, with a mass of sporocytes from Euduboscquella sp. (J) Tintinnopsis sp. lorica from Rhode River, MD, containing four sporocytes of Euduboscquella sp. (K) Lorica of Tintinnopsis cf. subacuta from Rhode River, MD, with a tomont of Euduboscquella sp. (arrow) located below host cell (H). (L) Tintinnopsis major lorica from Annapolis Harbor, MD, containing Euduboscquella sp. sporocytes. (M) Lorica of Tintinnopsis sp. from the Bay of Villefranche-sur-Mer, France, harboring a tomont of Euduboscquella sp.