Key: Step 19. 18

18a. Spiral striation faint, umbilicus narrow.

Lim.r.retroversa-

18b. Spiral striation faint, umbilicus broader.

Lim.r.australis-

Limacina retroversa australis

18c. Spiral striation evident, umbilicus narrow.

Lim.r.balea-

Decision path