Furcocercous cercariae shed by the freshwater snails Pila occidentalis (Mousson, 1887) and Biomphalaria pfeifferi (Krauss, 1848) in the Okavango Delta,Botswana
1. Department of Zoology and Entomology, University of the Free State, Bloemfontein, South Africa;2. Department of Biology, Sefako Makgatho Health Sciences University, Ga-Rankuwa, South Africa