ClipArt ETC
"Helix. A, an empty shell in section from apex to base...a, apex of shell; ap., aperture of shell; c, columella or axis of shell; l, lip of shell; s, suture, between whorls." -Galloway, 1915

Helix Shell

"Helix. A, an empty shell in section from apex to base...a, apex of shell; ap., aperture of shell; c,…

"Vertical section of the shell of a species of Helix. M., Mouth of shell; A., apex; C., columella." -Thomson, 1916

Shell

"Vertical section of the shell of a species of Helix. M., Mouth of shell; A., apex; C., columella."…