ClipArt ETC
"Diagrammatic vertical section through disc and base of one of the arms of Antedon rosacea. The section is inter-radial on the left, radial on the right. t., Ciliated openings in body wall; h., sub-epithelial ambulacral nerve; l., water-vascular canal; k., tentacle; r., mouth; s., intestine; g., central plexus, with "chambered organ" at its base; f., coelom; R1.-R3., radial plates; Br., brachial plates; u., muscle; a., axial nerve-cord; d., central capsule; C.D., centro-dorsal plate; p., cirri; e., nerve branches from central capsule to cirri." -Thomson, 1916

A. Rosacea Arm

"Diagrammatic vertical section through disc and base of one of the arms of Antedon rosacea. The section…

"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…