Figure 6-40.
Ventral view of a stage 28–29 embryo. The heart atrium appears below the ventricle (see also Movie M6-2f). Scale bar, 250 μm.

Figure 6-41.
Gene expression of mcmlc2 in the developing heart chamber structure of a stage 28 embryo, as detected by whole-mount in situ hybridization. Scale bar, 250 μm.