Fig. 2:

3D-reconstruction based on histological serial sections of Monobryozoon ambulans. A Lateral view showing the main parts of the lophophore and digestive tract. In addition, duplicature bands, funicular and retractor muscles are displayed. B Lateral view similar to A but showing parietal and apertural muscles. C Basal view showing the different appendages. D Lateral view with the body wall more transparently showing the distal muscle systems more clearly. a—anus, am—apertural muscles, b—bud, ba—basal appendage, cae—caecum, db—duplicature band, fg—foregut, fm—funicular muscle, int—intestine, l—lophophore, o—orifice, os—orificial sphincter, pm—parietal muscles, py—pylorus, rm—retractor muscles