GENERAL HISTOLOGY

Detailed explanation-1: -The lancelets are also called cephalochordates (Greek: kephale, “head”) because the notochord extends from near the tip of the tail to well into the anterior of the body. Because they do not have the braincase, or cranium, of a vertebrate, lancelets are often called acraniates.

Detailed explanation-2: -In common with vertebrates, lancelets have a hollow nerve cord running along the back, pharyngeal slits and a tail that runs past the anus. Also like vertebrates, the muscles are arranged in blocks called myomeres.

Detailed explanation-3: -Cephalochordata A subphylum or phylum of chordates that contains only the lancelets, a group of small invertebrate marine fishlike animals. There are 23 species in two genera – Branchiostoma (Amphioxus) and Epigonichthys.

Detailed explanation-4: -There are about 32 species of lancelets and one of them is Branchiostoma (Amphioxus) lanceolatus, a marine cephalochordate.