LampreysPetromyzonOncorhynchus kisutchReproductionFishesSalmonFish DiseasesHagfishesSeasonsSuperior ColliculiPhysiology, ComparativeVena Cava, SuperiorSpinal CordSwimmingMesenteric Artery, SuperiorVertebratesReticular FormationPyrrolidonecarboxylic AcidLocomotionChordata, NonvertebrateSuperior Vena Cava Syndrome