Trunkelongate, up to 1.5 mm long (Fritillaria borealis). Mouth with 2 lateral plates. Digestive tract axis oblique. Gonads symmetrically arranged. Testiselongate and simple, behind one spherical ovary, on the median axis of the trunk. Tail musculature from moderately broad to narrow.
Kingdom Animalia Phylum Chordata Subphylum Urochordata Class Appendicularia Family Fritillaridae Subfamily Fritillarinae Genus Fritillaria Subgenus Eurycercus Species Fritillaria borealis