The foraminifer Rosulina globularis dOrbigny from natural and laboratory populations is occasionally preyed upon by free-living, marine nematodes. Borings 3.7 to 14.3~ indiameter in the tests of living and dead specimens of R. globularis and dead specimens of Eolivina doniezi Cushman and Wickenden from the same natural and laboratory populations are attributed to the predaceous nematodes. Predation in the laboratory populations is greater than in the natural populations, especially among juvenile specimens of R. globuluris. Borings in R. globuluris occur characteristically in the outer whorl, whereas, those in B. doniezi are generally confined to the apertural half of the test. This preference for the area of wall penetration is thought to correspond to the accessibility or living position of the prey. However, several incomplete borings coincide with test pores, and thus represent test penetration in an area of least resistance. Identical borings occur in Holocene and Cretaceous bathyal and neritic foraminifers. Another kind of borings in these specimens, while in part resembling gastropod boreholes, may likewise be due to soft-bodied organisms. Evidence of predation provides ecologic and paleoecologic information on the living habits, habitat, and community structure of the foraminiferal prey, and can directly influence the interpretation of foraminiferal production and rates of sedimentation based on foraminiferal production.