"Dissection of snail. T., Short horn; TT., long horn with eye; N., cerebral ganglia; S.G., salivary…
"Helix. B, the relation of the animal to the shell when extended...a, apex of shell; an., anus; e, eyestalk;…
"Roman snail (Helix pomatia). Note shell covering visceral hump; p.ap., pulmonary aperture (including…
"Helix nemoralis. an, anus; gen. ap, genital aperture; oc. tent. posterior eye-bearing tentacles; pulm,…