ABSTRACT: The finding of a fossil specimen of the attached agglutinated foraminifera Ammolagena clavata (Jones and Parker) feeding inside the broken test of a Reophax is the basis for discussion about its food sourcing strategies. The study of morphological features, especially the position, course, and length of the tubular chamber ending in an opening, indicates that passive feeding played a significant role. The successive migration of the apertural part connected with the growth of the foraminifera enables access to new feeding areas on the surface of the settled substrate or on the sediment surface.