Add to ORKGNot AvailablePycnogonids, popularly known as sea spiders, are a strange group of entirely marine arthropods belonglng to the phylum Arthropoda and class Pycnogonida (Gr. pyknos = crowded; gony = knee), which means 'knobby knees'. They are more closely relaled 10 spiders rather than to crustaceans (shrimps, lobsters, etc).Not Availabl