Ventral muscle anatomy in H. dujardini as revealed by phalloidin staining. Specimens are oriented ventral side up. Anterior is to the top. Scale bars equal 25 μm. (A) Depth-coded maximum projection of ventral slices of confocal Z-series. Ventral median attachment sites are numbered 1-7. Muscle strands are labeled following the system of Schmidt-Rhaesa and Kulessa . The first attachment site is out of focus below the pharyngeal bulb. We have outlined its position. Inset shows a maximum projection of the first attachment site. Intermediate attachment sites along one ventral longitudinal muscle strand are boxed. (B) Scanning electron micrograph showing cuticular depressions associated with ventral attachment sites. Abbreviations: mo, mouth; ph, pharyngeal bulb; ve, ventral longitudinal muscle; vi, visceral muscle.