Handling of Helobdella (leech) embryos

Gravid Helobdella (leech) adults are identified by white egg masses that are visible through the ventral body wall. For convenience, gravid animals should be moved to smaller bowls so that those animals with newly laid embryos can be more readily identified. Zygotes (fertilized internally) turn pink when they are deposited into transparent cocoons on the ventral surface of the parent. A typical clutch consists of 20-100 embryos. Embryos can be collected after zygote deposition and before hatching (stage 10). This article describes how to collect and culture Helobdella embryos.