Development of Branchiostoma (Amphioxus) is indirect involving a larval stage. Early embryology of Branchiostoma is simple. Therefore, the transformation of egg, which having less yolk, into a complex and differentiated animal is far easier to follow than in any other vertebrate. The early development of Branchiostoma (Amphioxus) is of great phylogenetic significance because it resembles with those of invertebrates like [...]
In this article we will discuss about the external morphology of branchiostoma with the help of suitable diagrams. Shape, Size and Colour: Branchiostoma is about 3.5 to 6.0 cm in length. The body is slender, somewhat translucent, superficially fish-like, laterally compressed and pointed at both ends, hence, the name lancelet. The anterior two-thirds of the body is roughly triangular in [...]
In Branchiostoma, nervous system is simple, having no brain as found in higher chordates. Nerve Cord: There is a mid-dorsal, hollow, tubular neural tube or nerve cord lying above the notochord. It starts behind the anterior end of the notochord and tapers to a point posteriorly and ends a short way in front of the hinder end of the notochord. [...]