Biology · Ch 4 — Kingdom Animalia
Subphylum Cephalochordata
Subphylum Cephalochordata
Subphylum Cephalochordata includes Branchiostoma (commonly called Amphioxus or lancelet). These animals are exclusively marine, small, fish-like in shape, and rarely exceed about 5 cm in length. Lancelets live partly buried in soft marine sediment.
Unlike Urochordata, the notochord in Cephalochordata extends along the entire length of the body and persists throughout life, not just in a larval stage. The body also shows segmented muscle blocks called myotomes, and a post-anal tail — a tail that extends beyond the anus. …
What this figure shows. A longitudinal, labelled diagram of the slender lancelet body showing the buccal cirri around the mouth, the vestibule, pharynx with gill slits, the notochord and dorsal hollow nerve cord running its length, segmented myotomes, the midgut with its diverticulum, the atriopore, and a caudal fin …