Figure 9

Musculature of the slime papillae associated with the ventral and preventral organs. Confocal laser-scanning micrographs of embryos of Euperipatoides rowelli (Peripatopsidae) labelled with phalloidin-rhodamine (f-actin; glow scale). Anterior is up in all the images. (A) Overview of the musculature of the head in a stage VI embryo in ventral view. Arrows indicate the anterior depressor muscles of the slime papillae. (B) Detail from the same embryo as in A showing the attachment of the anterior depressor muscle (arrow) to the anlage of the preventral organ. Note the sensilla of the developing last pair of lips (arrowhead) situated posteriorly to the preventral organ. (C) Overview of the musculature of the head in a late stage VII embryo in ventral view. At this stage, the ventral and preventral organs of the slime papilla segment have been separated by the posterior-most pair of lip papillae (arrowheads). Note the posterior pair of depressor muscles of the slime papillae that are attached to the corresponding ventral organ situated posterior to the mouth. Abbreviations: an, presumptive antenna; ho, anlage of the hypocerebral organs; jw, presumptive jaws; pd, posterior depressor muscle of the slime papilla; pv, anlage of the preventral organ; sp, presumptive slime papilla; to, presumptive tongue; vo, anlage of the ventral organ. Scale bars: 100 μm.