Key Position: 5 Back to (3b)
5 a. Apertural lip thickened and at an angle of 45-60 degrees with respect to the test; spines absent.

SEE Figure 5-1

 5 b. Apertural lip thickened and at an angle of 45-60 degrees with respect to the test; spines present.

Proceed to 6
FIGURE 5-1

Centropyxis constricta (Ehrenberg 1843) "aerophila"
Centropyxis aerophila DEFLANDRE 1929
Centropyxis aerophila Deflandre OGDEN and HEDLEY 1980, p. 48-49
Cucurbitella [sic.] constricta REINHARDT et al. 1998, pl. 1, fig. 6
Specimen from Peterson Lake, near Cobalt, Ontario.