Fig. 2. Ca²⁺ influx during the second phase of Ca²⁺ waves. Fura-2-dextran-injected eggs were fertilized in natural (normal) sea water (SW) (shaded box). Following the first Ca²⁺ wave, individual eggs were then removed from the wedge and transferred to a large excess of Ca²⁺-free sea water (CaFSW: stippled box; approx. 5 µl into 2 ml) supplemented with 2 mM EGTA. Once the eggs had sunk to the bottom of the CaFSW imaging was restarted. (A) The temporal pattern of Ca²⁺ oscillations is displayed for an egg transferred to CaFSW. The transfer to CaFSW took 1 minute. Following transfer to CaFSW, the second phase of Ca²⁺ oscillations were present (7 waves in total in this particular egg). (B) The origin of each of the 7 waves is displayed. The white arrowhead indicates the location of the CP and the black arrowhead the location of the pb1. Temperature 19°C, n=5 replicates, 3 animals.