English: Movie 4: Precursors of the corpus and posterior bulb. 3D animation showing side by side left and ventral views of the embryo during the inflation stage of pharyngeal development. See legend of Figure 5II for coloring scheme. The movie illustrates the detailed reshaping of the pharynx from 197 through 337 minutes. In the later half of the assembly stage (197 to 250 minute), the two sheets expand in size through division. During the final round of synchronized divisions between ~277 and 307 the pharynx contracts along the AP axis rounding slightly. On the completion of divisions this structure then inflates to form a roundish structure[33] prior to its eventual elongating and spitting into two chambers (not shown). This ballooning is apparent from time 317 onward and occurs at the same time as the ventral MS pharynx cells move anteriorly toward the main mass of the pharynx. The movie also highlights the mouth precursors being born relatively distant from their final positions and converging near their final location.