"Lateral view of Amphioxus. The notochord runs from tip to tip. t., Tentacular cirri; G., reproductive organs; a.p., atriopore; a., position of anus; 40 and 62, indicate number of myotomes." -Thomson, 1916

Lancelet

"Lateral view of Amphioxus. The notochord runs from tip to tip. t., Tentacular cirri; G., reproductive…

"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;…

"Amphioxus lanceolatus. A, ventral; B, side view of the entire animal. an, anus; atrp, atriopore; cd. f, caudal fin; cir, cirri; dors. f, dorsal fin; dors. f. r. dorsal fin-rays; gon, gonads; mtpl, metapleure; myom, myomeres; nch, notochord; or. hd, oral hood; vent. f, ventral fin; vent. f. r, ventral fin-rays." -Parker, 1900

Lancelet

"Amphioxus lanceolatus. A, ventral; B, side view of the entire animal. an, anus; atrp, atriopore; cd.…

"Amphioxus lanceolatus. A, transverse section of the pharyngeal region. a, dorsal aorta; b, atrium; c, notochord; co, coelom; e, endostyle; g, gonad; kb, branchial lamellae; kd, pharynx; l, liver; my, myomere; n, nephridium; r, neuron or dorsal nerve tube; sn, spinal nerves; sp, gill-slits. B, transverse section of the intestinal region; atr, atrium; coel, coelom; d. ao, dorsal aorta; int, intestine; myom, myomere; nch, notochord; neu, neuron; s. int. v, subintestinal vein." -Parker, 1900

Lancelet Section

"Amphioxus lanceolatus. A, transverse section of the pharyngeal region. a, dorsal aorta; b, atrium;…