Keywords: Conchological Manual Fig 16.png Fig 16 Measurement of Symmetrical Conical Univalves The width is measured across the aperture which is the widest part of the shell The length l from the dorsal part d of the aperture to the dorsal part of the whorl d on the opposite part of the shell The ventral part of the whorls is that nearest to the axis and the dorsal that which forms the outline of the figure gutenberg A Conchological Manual 43417 1842 George Brettingham Sowerby II 1812 “1884 PD-old-100 A conchological manual 1842 |