Departamento de Ginecología y Obstetricia, Facultad de Medicina, Universidad de Concepción, Concepción, Chile.

These are eight-week conjoined twins.

Figures 1 and 2: Note the peculiar bifid shape of the embryo (Omega shape).

Figure 3: Note the two heads at each end of the embryonic image. In the figure of the right hand side, note the two amniotic sacs, with no inter amniotic membrane. The  most probable union is Pygopagus.

Figures 4 and 5: This is the Doppler image which demonstrates the shared circulation between the embryos. Also the two fused amnions are seen.