Keratella is a footless rotifer which posesses a protective covering, or lorica. Keratella cochlearis occur in two body forms. The tecta form exists without the posterior spine displayed by the typica form. Generally, spines are present on those Keratella which are born in the presence of predators such as cladocerans, Asplanchna and cyclopoid copepods. The typica form can be born from a tecta mother and vice versa (Gilbert and MacIsaac, 1989).