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 [...]
The body wall (Fig. 6.4) is formed of outermost thin, transparent skin, well-developed musculature and a parietal peritoneum. Skin: There is a thin, outermost, perforated cuticle covering an epidermis which, unlike vertebrates, is made of a single layer of columnar epithelial cells. These are placed on a basement membrane. Cuticle is secreted by the epidermal cells. In between the epidermal [...]