ИСТИНА

Ascothoracida are parasites of anthozoans and echinoderms. Many brood their nauplius larvae, release lecithotrophic nauplii, or undergo embryo- genesis directly to the subsequent a-cyprid stage. Some, however, release apparently planktotrophic nauplii with long, heavily armed appendages. Their bobbing motion while swimming and the grand, sweeping movements of their antennae are distinctive, but photographs of living ascothoracidan larvae are rare, and no videos appear to be available to zoologists. In September, 2017, at Green Island, Taiwan, we employed semi-high-speed (162 fps) video photography using an Olympus IX70 inverted microscope, a Basler ace USB 3.0 digital camera with a SONY sensor (1936 x 1216 pixels), and various software (e.g., TroublePix ver. 2.35.0.6095, Filmora ver. 8.4.0) to docu- ment the limb movements and body motions during swimming of first- and/ or second-instar nauplii of Sessilogoga sp. (Synagogidae) and Petrarca sp. (Petrarcidae) released in the laboratory by adults infecting antipatharian and scleractinian corals, and nauplii of probable Baccalaureus sp. (Lauridae) from the plankton. Behavior of laurid a-cyprids (so-called “Tessmann’s larvae”) from the plankton was recorded the same way. SEM micrographs were also taken. It is noteworthy that the naupliar antennules do not simply point forward, but bend downward to participate in the power stroke, and that the mandibles’ movements are restricted compared to those of the antennae. The laurid and petrarcid larvae are morphologically similar to others of these families described earlier using light microscopy, but the nauplii of Sessilogoga differ from known forms in the cephalic shield outline and distribution of marginal pores.