• (n. pl.) The lowest group of vertebrates; -- so called from the cirri around the mouth; the Leptocardia. See Amphioxus.
Cir`ros'to·mi noun plural [ New Latin , from English cirrus + Greek ... mouth.] (Zoology) The lowest group of vertebrates; -- so called from the cirri around the mouth; the Leptocardia. See Amphioxus .