Stage 12 (Protruding first antennae): (a-b) SEM; (c, d) Congo-red. (a) Ventro-lateral view: the overall shape of the embryo changed to a crookbacked shape due to modifications of the anterior carapace. The head is now covered by the carapace and the first antennae are protruding. In females, the first antenna fuses completely at this stage. The second antennae are almost as long as the whole body. The labrum has continued its elongation and narrowing of the tip. (b) The setae and setae on the first to fourth thoracopod have enlarged. The number and size of the setae on the fifth thoracopod have increased. The proctodeum moved further anterior due to the growth of the abdomen. The carapace spine has further elongated and bends in antero-ventral direction. (b‘) Detail of the thoracopods showing the enlargement of the setae. (c) Ventral view. (d) The lateral view shows the change in overall habitus leading to the typical crookbacked Daphnia-habitus. The carapace spine elongated and bends in antero-ventral direction. a1, a2 = first and second antennae; ab = abdomen; ca = carapace; casp = carapace spine; gi = gill; lb = labrum; md = mandible; mxa = maxillary appendage; pro = proctodeum; thp = thoracopod.