Trunk flattened, up to 1.4 mm long (Fritillaria antarctica). Mouthbilobate. Four pharyngeal cells. Spiracles oval and large. Axis of the alimentary tract transverse. Testis lobed, clasp-shaped, surrounded by one cord-like ovary.
Kingdom Animalia Phylum Chordata Subphylum Urochordata Class Appendicularia Family Fritillaridae Subfamily Fritillarinae Genus Fritillaria Subgenus Acrocercus Species Fritillaria antarctica