Gametogenesis in the Monothalamous Agglutinated Foraminifer Cribrothalammina alba

ABSTRACT Gametogenesis in the foraminifer Cribrothalammina alba involves changes in both the gamontic test and cytoplasm. As gametes begin to differentiate and gametic flagella emerge, pores form in a regular array over the gamontic test, constituting the only avenue for gamete release. The spherical, biflagellated gametes average 1.5μ in diameter and are released in rapidly moving swarms along with flagellated “spherical masses” that probably result from incomplete gametic differentiation. Gametogenesis occurs entirely within the test and utilizes the entire cytoplast. After gamete release is complete, the agglutinated test collapses and disaggregates within a fairly short time. Similar modifications of the gamontic test occur during gametogenesis in Ovammina opaca Dahlgren, but are otherwise unknown among monothalamous agglutinated foraminifera at present.