Studies of Feeding Behavior of Amebas. I. Ingestion of Thecate Rhizopods and Flagellates by Verrucosid Amebas, particularly Thecamoeba sphacronucleolüs.*

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Abstract
SYNOPSIS.: Thecamoeba sphaeronucleolus, and other verrucosid amebas with thick, pellicular ectoplasm, which live in moist soil, can identify the presence of testate rhizopodal prey at distances of 20 to 30 μ, possibly chemotactically or rheotacti‐caliy. Prey is seized by extension of a pseudopod towards it, and adhesion of the pellicular pseudopodal tip to the prey upon contact. Ingestion is accomplished by conversion of the pellicular coat of the pseudopod into an ingestive tube via digestion of the pellicular tip and the withdrawal of the endoplasm within, causing suction. The prey is drawn into the tube and enclosed therein; and is then drawn down the pseudopodal tube and into a food cup, which closes around the prey to form a food vacuole. Flagellate prey is identified by its movements nearby, and is seized by adhesion of the extended pseadopod to a flagellum. The flagellum is drawn through a tiny hole digested by the ameba through the pellicle of its psendopod. is seized by and drawn into the granular endoplasm. The body of the flagellate is drawn after it into a food vscuoie in the endoplasm. Suction applied to the flagellum appears to exert the necessary force to draw the flagellate in. The movements involved are related to, but not synonymous with, those of locomotion and appear to be complex biochemical and biophysical interactions not explainable by present theories of protoplasmic movements.