Bullinularia gracilis Thomas, 1959

Diagnosis: Shell ellipsoid, chitinoid, with a thin covering of xenosomes, though sometimes lacking xenosomes entirely. Pores and pseudostome as in B. indica, but much smaller. Colour from bright yellow to brown; test transparent.

Dimensions: Thomas (1959): about 120 µm. My measurements: 117–164 µm.

Ecology: Soil, mosses.

Remarks: (From Lueftenegger & Foissner.) Hoogenraad & De Groot (1952) describe two shell types for B. indica: the ‘extraordinary’ type, which is firm and inflexible, and the ‘normal’ type, which is flexible and rather tenacious, consisting of a homogeneous matrix, as also noted by Penard (1912). We suggest that the outer organic layer, which appears to be somewhat elastic, is responsible for the flexibility observed in shells of some Bullinularia populations.