1 Shell dimensional variables considered for statistical analysis. Abbreviations: AH aperture height, AW aperture width, LWfW last whorl final width, LWmW last whorl medial width, LWH last whorl height, LWaH height of adapical sector of last whorl, LWmH height of medial sector of last whorl, PWH penultimate whorl height, PWfW penultimate whorl final width, PWmW penultimate whorl medial width, SD shell diameter, SH shell height, UD umbilicus diameter 2 Genital dimensional variables considered for statistical analysis. Abbreviations: F flagellum, E epiphallus, P penis, DBC duct of bursa copulatrix, V vagina, VA vaginal appendix.