The medicinal leech was once widespread in Britain but its numbers have declined dramatically.

A rare breed of blood-sucking leech is being bred at London Zoo in a bid to save the UK’s largest native leech species from extinction. The medicinal leech was once widespread in Britain, but ...

Piscicola has a pair of elongated sac-shaped ovaries. Inside the ovaries are numerous small somatic cells and regularly spherical egg follicles. Each follicle is composed of three types of cells ...