Figure 4

Myoanatomical details of the polypide of Hislopia malayensis. All but (a) are maximum-intensity projections of confocal laserscanning image stacks. (a) Volume rendering of the confocal stack of the myoanatomy of a dissected polypide showing most of the musculature of the digestive tract. (b) Oblique view on the vestibular wall showing apertural muscles and vestibular wall muscles. Diagonal vestibular wall muscles can be distinguished on the basal side. (c) Detail of the tentacle musculature and muscular concentration at the tentacles tips (open arrowheads). (d) Musculature of the esophagus showing thin longitudinal muscle fibres. (e) Lophophoral base musculature and parts of the digestive tract. Asterisk marks a second pair of buccal dilatators. (f) Detail of the tentacle sheath musculature and apertural muscles. (g) Magnified view of the distal portion of the retractor muscles displayed in (e). (h) Muscular elements of a rosette plate between individual zooids. (i) Musculature of the proventriculus and adjacent parts of the digestive tract. Double arrowheads marks fine longitudinal muscle fibres in the caecum. Abbreviations: a - anal area, am - apertural muscles, bd - buccal dilatators, brm - ring muscle at the lophophore base, cae - caecum, clm - caecal longitudinal muscle, ds - diaphragmatic sphincter, dvm - diagonal vestibular wall musculature, es - esophagus, int - intestine, lb - lophophore base, les - longitudinal musculature of the esophagus, llb - longitdunal muscles at the lophophore base, pm - parietal muscles, pv - proventriculus, rm - retractor muscles, tm - longitudinal tentacle muscles, ts - tentacle sheath, vlb - v-shaped muscles at the lophophore base, vwm - vestibular wall musculature, yb - young bud.