Larval common slipper shells (Crepidula fornicata) have a high degree of control of velar lobe extension and orientation. This 19 day old individual swam upward with only one of two velar lobes fully extended. Video captured at 2000 fps and replayed at 200 fps.
Chan K, Jiang H, Padilla D
CC BY 4.0
Video S1 from <cite style="font-style:normal">Chan K, Jiang H, Padilla D (2013). "<a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3867405">Swimming Speed of Larval Snail Does Not Correlate with Size and Ciliary Beat Frequency</a>". <i>PLOS ONE</i>. <a href="https://en.wikipedia.org/wiki/Digital_object_identifier" class="extiw" title="w:Digital object identifier">DOI</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1371/journal.pone.0082764">10.1371/journal.pone.0082764</a>. <a href="https://en.wikipedia.org/wiki/PMID" class="extiw" title="w:PMID">PMID</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pubmed/24367554">24367554</a>. <a href="https://en.wikipedia.org/wiki/PubMed_Central" class="extiw" title="w:PubMed Central">PMC</a>: <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3867405">3867405</a>.</cite>