The prehistoric vertebrate, the lancelet or Amphioxus.

Lancelet

The prehistoric vertebrate, the lancelet or Amphioxus.

"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…

"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.…

The prehistoric chordate, the Ascidian or sea squirt.

Sea Squirt

The prehistoric chordate, the Ascidian or sea squirt.