Janickina E. Chatton ex Grassé 1953

Active locomotive cell elongate, usually 75 to 100 µm in length, with an eruptive motion. Nucleus ovate with an irregular nucleolus (endo-some). Adjacent to the nucleus is a paranuclear 'amphosome', ultrastructurally identical to the parasomes of Neoparamoeba and Paramoeba. In Janickina, this DNA-rich inclusion is approximately 30 µm and divides synchronously with the nucleus. Cytoplasm without crystals or contractile vacuoles but with numerous vesicles and granules. No cysts reported. Parasite of the chaetognaths, Spadella spp. and Sagitta spp.