Fig. 2. Early development of Alvinella pompejana after in vitro fertilisation and incubation at 26 MPa. (A) Oocyte just after fertilisation. (B) Fertilisation envelope. (C) First polar lobe. (D) 2-cell stage. (E) 4-cell stage. (F) 8-cell stage. (G) 12-cell stage. (H) >12-cell stage. A and B are from cultures incubated at atmospheric pressure, 5 and 30 min after fertilisation, respectively. Embryos in C, D, E and G were obtained after in situ incubation at the bottom of the ocean at 5°C for 5 days. Embryos in F and H were obtained after incubation in pressure vessels at 10°C for 72 h and 96 h, respectively. Scale bars, 50 µm.