File:Schematic mollusc.jpg

English: From The sea-beach at ebb-tide : a guide to the study of the seaweeds and the lower animal life found between tidemarks. Augusta Foote Arnold. 1901. p. 318. Title is "Ideal or schematic mollusc", another term for "hypothetical ancestral mollusc". 1, dorsal view: h, head; t, cephalic tentacle; sh., shell covering visceral mass; b.m., outline of

body-mass; r. m. e., edge of mantle; c. t., ctenidia, or -gills; q. ., generative apertures ; r. e., renal openings ; e. o., excretory opening; /, posterior portion of foot ; o. e. m., edge of shell. 2, ventral view : ft, head; t, tentacle; m, mouth; 6, outline of body; e.m., edge of mantle; s.f., lower surface of foot ; c. t., ctenidia, or gills ; /, posterior portion of foot. 3, horizontal section, showing heart, nephridia, and gonads : m, mouth ; o, esophagus ; g, gonad ; p, pericardium; n, nephridium. or renal organ; v, ventricle; a, auricles; g', gonad aperture; n', renal opening ; e, excretory opening ; /, posterior portion of foot. 4, vertical median section: m, mouth; b.m., buccal mass; I, liver; A. a., digestive tract; q, gonad; /, foot ; q. o., gonad aperture, or opening of oviduct; r. o., renal opening ; e. o., end of digestive tract, excretory opening; n, mantle; r, nephridium, or renal organ; o. /., recurved portion of

mantle; sh., shell; v, ventricle; p, pericardium.