Order Beroida:

Ctenophores in order Beroida have no tentacles.
Beroe Ovata
Beroe ovata lack tentacles throughout the life cycle. Instead of tentacles, they have large oral lobes and a cavernous lobes. Their bodies resemble a swimming sac. Beroe ovata is native to colder waters. Unlike most ctenophores, Beroe does not eat crustacean zooplankton, but prefers dining on other ctenophores. The primary food source for Beroe ovata is Mnemiopsis ledyi. Beroe ovata is considered an invasive beroe_ovata.jpgspecies in the Black Sea region. After its detection in 1997, Mnemiopsis populations have greatly declined in recent years. Some scientists are thinking of introducing Beroe to the Capsian Sea as a potential solution to the overpopulation of Mnemiopsis in the area.
Some Beroe use modified mouth cilia to bite their prey while larger Beroe use their cilia to grab and swallow their prey whole. Beroe are relatively strong swimmers because eight-comb rows of cilia. Beroe ovata spends most of its time swimming in search of prey. Like other ctenophores, some areas of the Beroe body are luminescent. While Beroe ovata are sometimes displayed in aquariums, they usually cannot be bred in captivity.

Beroe ovta, mouth agape.
Beroe ovta, mouth agape.

VIDEO: Swimming B. ovata