"Diagram of the anatomy of Amphioxus, drawn as a semi-transparent object. a, anus; a.p., atrial pore; c.f., caudal fin; cir., cirri, on the edge of the vestibule leading to the mouth; d.f., dorsal fin; r, fin rays; g, gill or branchial structures consisting of alternate slits, through which the water passes, and supporting pates, in the walls of which are the blood vessels; in., intestine, from which as a diverticulum springs l., the liver; m, the mouth surrounded by a ringed velum; my., myotomes or muscle segments; n.c., notochord; o., ovaries; s.c., spinal cord; v.f., ventral fin." -Galloway, 1915

Lancelet

"Diagram of the anatomy of Amphioxus, drawn as a semi-transparent object. a, anus; a.p., atrial pore;…