protoavis: most primitive avian type known; extinct bird of the Triassic having bird-like jaw and hollow limbs and breastbone with dinosaur-like tail and hind limbs
chordate: any animal of the phylum Chordata having a notochord or spinal column
ringer's solution: an aqueous solution containing the chlorides of sodium and potassium and calcium that is isotonic to animal tissues; used to correct dehydration and (in physiological experiments) as a medium for in vitro preparations