Figure 37 Fig. Morphogenesis of the pectoral bud during the late pharyngula period. Left side Nomarski views from the ventrolateral aspect of the embrytshow the bud in relief. Dorsal is to the top, anterior is to the left.
Arrows indicate the boundary between the bud's surface epithelium and inner mesenchyme.
The common cardinal vein passes just anteriorly, beneath the epithelium. The focus is along the prominent apical ectodermal ridge, crossing the bud distally.