leptocardia

leptocardia is a   Noun

Definition:

[1] 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.]

Synonyms: