Order: Like choanoflagellates, but second trailing flagellum attaches to base of lorica; colars indistinct, rudimentary (How to know the protozoa, 1979).
Genus: With vase-like lorica; body small, ovoid with rudimentary collar, a flagellum extending through it; protoplasmic body anchored to base by a contractile filament (Kudo, 1966).
Subgenus: sessile, colonial.
B. petiolata
DSR images
Japan, 199?
B. petiolata
PhotoCD images
Japan, 199?
B. petiolata
Gyoda
Saitama, 2001
