Figure 2.

Distinct morphological features allow the identification of the ventral and dorsal sides of an embryo

DIC images of an embryo at one moment between 320-330 min post the 1^st cleavage (the first embryonic cell division). Scale bars are 10 mm.

(A and B) The same image of the ventral side of an embryo.

(C and D) The same image of the dorsal side of the same embryo.

(B, D) The ventral (B) and dorsal (D) hypodermal cells, the distinct organization patterns of which allow the viewer to distinguish the ventral from the dorsal surfaces, are highlighted in purple.