An Account of Amoeba discoides; its Culture and Life History

ABSTRACT A large free-living amoeba found by Mr. Harry Watkinson in the tropical fish tanks of Mr. Albert Sutcliffe of Grimsby has been identified as Amoeba discoides (Schaeffer, 1916) = Metachaos discoides (Schaeffer, 1926). From the inoculation material obtained from these tanks Amoeba discoides has been successfully cultivated in the Notre Dame Training College Laboratory by a technique similar to that used for the cultivation of Amoeba proteus: wheat being the pabulum employed. In contrast to what obtains in the cultivation of Amoeba proteus, however, Amoeba discoides flourishes more luxuriantly in shallow Petri dishes, than in deeper troughs. The nucleus in the resting and dividing stages is described; division is amitotic. The more important cytoplasmic contents, including nutritive spheres, and crystals are likewise described. The life-history has been worked out. The adult amoeba becomes an agamont giving rise to agametes which eventually grow into adult amoebae, the life-cycle occupying roughly about four months. Descriptions of the nucleus of the newly hatched and developing amoebae are deferred.