Lep`to*car"di*a (?), n. pl. [NL., fr. Gr. small + the heart.] Zool.
The lowest class of Vertebrata, including only the Amphioxus. The heart is represented only by a simple pulsating vessel. The blood is colorless; the brain, renal organs, and limbs are wanting, and the backbone is represented only by a simple, unsegmented notochord. See Amphioxus.
[Written also Leptocardii
© Webster 1913.