Toward an atlas of Salish Sea biodiversity: the flora and fauna of Galiano Island, British Columbia, Canada. Part I. Marine zoology Author Simon, Andrew D. F. https://orcid.org/0000-0002-5358-8974 Institute for Multidisciplinary Ecological Research in the Salish Sea, Galiano Island, Canada adfsimon@imerss.org Author Adamczyk, Emily M. Institute for Multidisciplinary Ecological Research in the Salish Sea, Galiano Island, Canada & University of British Columbia, Vancouver, Canada Author Basman, Antranig Institute for Multidisciplinary Ecological Research in the Salish Sea, Galiano Island, Canada Author Chu, Jackson W. F. https://orcid.org/0000-0002-7776-9446 University of Victoria, Victoria, Canada Author Gartner, Heidi N. Royal British Columbia Museum, Victoria, Canada Author Fletcher, Karin Port Orchard 98366, Port Orchard, United States of America Author Gibbs, Charles J. Pacific Marine Life Surveys, Port Coquitlam, Canada Author Gibbs, Donna M. Pacific Marine Life Surveys, Port Coquitlam, Canada Author Gilmore, Scott R. 7494 Andrea Cres, Lantzville, Canada Author Harbo, Rick M. Royal British Columbia Museum, Victoria, Canada Author Harris, Leslie H. Natural History Museum of Los Angeles County, Los Angeles, United States of America Author Humphrey, Elaine Institute for Multidisciplinary Ecological Research in the Salish Sea, Galiano Island, Canada & University of Victoria, Victoria, Canada Author Lamb, Andy Pacific Marine Life Surveys, Port Coquitlam, Canada Author Lambert, Philip Royal British Columbia Museum, Victoria, Canada Author McDaniel, Neil McDaniel Photography, Vancouver, Canada Author Scott, Jessica Ocean Wise, Vancouver, Canada Author Starzomski, Brian M. University of Victoria, Victoria, Canada text Biodiversity Data Journal 2022 2022-03-10 10 76050 76050 http://dx.doi.org/10.3897/BDJ.10.e76050 journal article http://dx.doi.org/10.3897/BDJ.10.e76050 1314-2828-10-e76050 440282C625BD5D90A9623563DB6850F5 Chaetognatha Leuckart, 1854 Notes [ 1 class ] The name ' Chaetognatha ' derives from the Greek xαίτη ( khaitē ), meaning "bristle" , and γνάθος ( gnathos ), meaning "jaw" . Chaetognatha (arrow worms) are a small phylum of predatory animals, all of which are marine, including 130 extant species in the class Sagittoidea ( WoRMS Editorial Board 2021 ). Though they are not diverse, arrow worms are extremely numerous, representing a major component of marine plankton worldwide. Of the six species of arrow worm known to the Northeast Pacific, four have been sampled in the waters off the coast of British Columbia ( Lea 1955 , Gardner 1982 ). Parasagitta elegans (Verrill, 1873) (Fig. 9 ) is the most abundant species reported from the sheltered inland waters of the Salish Sea ( Lea 1955 ). Eukrohnia hamata ( Moebius , 1875) is also known to occur infrequently in inland channels, as an oceanic species that is occasionally borne in by the intrusion of offshore waters ( Lea 1955 , Gardner 1982 ). It is not possible to determine chaetognath reports in the Galiano Island record as they are based on dive observations, but studies indicate that, in all likelihood, these observations refer to P. elegans . Sampling by use of plankton tows and microscopic analysis would help confirm the local fauna. Chaetognaths are active predators, grasping their prey with two sets of rigid hooks located at the sides of the head, hence the common name "bristle-mouth." These predatory animals are chiefly pelagic, occurring in the open ocean. Appearing like a glass arrow in the water, chaetognaths swim by flexing in the middle of the body, which is supported by a hydrostatic skeleton. The lateral fins on either side of the body appear to aid buoyancy, but are not involved in movement. As few species are present locally, students may disregard more cryptic characteristics and distinguish species by focusing on the arrangement of lateral fins and eye colouration ( Lea 1955 ). For a treatment of British Columbia's chaetognaths, including a set of technical keys, see Wailes (1929) , Lea (1955) , Bieri (1959) , Gardner (1982) , Kozloff (1996) , Lamb and Hanby (2005) and Carlton (2007) provide additional accounts. For annotated records of chaetognaths reported for Galiano Island, see supplementary materials (Suppl. material 7).