Luffisphaera cucumiformis Belcher & Swale, 1975
Diagnosis: With the characteristics of the genus. Cells spherical or oval, 2.3-2.8 µm x 1.7-2.0 µm. Bowl-shaped basal parts of the scales ca. 0.3 µm x 0.2 µm x 0.13 µm deep. Below the distal rim are two rows of roughly rectangular perforations, the upper larger than the lower, the remainder of the wall of the bowl consisting of a fine indistinct network. The outer part of the scale is ca. 2.5 µm long (range 2.1-2.9 µm) and narrows proximally to a waist before expanding to join the major portion, an irregular cylinder tapered at each end. The cylinder reaches a maximum width of a little less than 0.2 µm and bears about nine longitudinal ribs. Distally the number of ribs decreases, usually to five, and the scale ends in a truncate tip. Between the ribs there are generally two rows of hexagonal pores.
Ecology: freshwater, Great-Britain