Hoogenraadia cryptostoma Gauthier-Lièvre & Thomas, 1958

Diagnosis: Shell ovoid elongated; compared to the length, the width is greater which gives the whole a massive and heavy look. The pseudostome is surmounted by a visor that covers it while being rolled up on itself. The pseudostome, which is terminal and circular or nearly so, is concealed by this visor which is only the extension, on one side, of the sides of the test. The test seen in profile, according to whether it is examined in a right or left position, takes the form of the number 6. In front view the visor completely hides the aperture, in side view its free edge draws, near the pseudostome, a sinuous line that is reminiscent of the lip in Bullinularia. The test is chitinoid, brownish yellow, covered with well-fixed platelets, larger on the body, never overflowing as it is observed at Centropyxis and Cyclopyxis.

Dimensions: According to Gauthier-Lièvre and Thomas (1958): Shell length 130—140 μm; width 105—110 μm; depth 85—90 μm.

Ecology: River.

Geographical distribution: Africa: Middle Congo.

Remarks: This species differs from H. africana, of which it is very near, by superior dimensions; Another special feature is the shape and layout of the visor.

This species was found in a station rich in individuals of H. africana, mixed with them. These forms are particularly interesting because both species show a more and more advanced cryptostomy, a character which, until now, has been found only in testate amoebae strictly living in soil (Gauthier-Lièvre and Thomas, 1958).