English: A phylogenetic classification of animals (for the use of students). By W.A. Herdman. Published 1885 by Macmillan and Co., Adam Holden in London, Liverpool . p. 30.

Fig. 15, Archi-Mollusc. Three diagrammatic views taken from Lankester's figures. A, Vertical antero-posterior section. B, Dorsal view, in which the bodywall is supposed to be transparent, allowing the circulatory, renal, reproductive, and other organs to be seen through. C. Ventral view shewing the nervous system, a, cephahc tentacle; b, head; c, free edge of mantle skirt; d, anus; e, edge of the foot; f. edge of the shell follicle ; g. gonad, or reproductive organ; go opening of duct from gonad ; h, osphradium ; i, ctenidium ; k, liver ; l, nephridium ; l', opening of nephridium ; m, mouth ; n, posterior end of foot ; o, cephalic eye ; r, auricle of heart; s, pericardium; v, ventricle of heart, giving off an anterior and a posterior vessel; y, otocyst; g.a, abdominal ganglion; g.c, cerebral ganglion ; g^.o, olfactory ganglion; g.p, pedal ganglion; g.pl, pleural ganglion; g.v, visceral ganglion;

n.p, pedal nerve ; n.v, visceral nerve.