LEIDYS COMB JELLY

Defining physical characteristics:
Combs/Ctenes: Each row or band of very long cilia fused into ctenes or combs (Greek: ctene = comb). Swimming is accomplished by the beating of the ctenes. Ctenophores are the only animals that have their cilia fused into ctenes. The ctenes are usually organized into eight rows which are evenly spaced around the body.

Comb rows: Plates of fused cilia arranged in rows or combs, extending from the oral to the aboral surface of the animal. Comb rows are iridescent.

Apical sense organ: controls the activity of the comb rows by means of nerve impulse conduction. This organ is involved in balance and controlling direction the organism moves toward or away from. It is located at the aboral (away from mouth) end of the ctenophore

Colloblasts: Adhesive prey-capturing cells on the oral lobes. Each colloblast cell consists of a bulbous, sticky head connected to a long, straight filament and a spiral, contractile filament. Prey become stuck to colloblasts and oral lobes move food to mouth.

Oral Lobes: tentacles covered with mucus and colloblasts which act as the food collection surfaces. Muscular activity of the two oral lobes also aids in locomotion.

Auricles: two pair of paddle-like structures also assist in prey capture

Muscle tissue: Ctenophores possess smooth muscle tissue, which is used by the oral lobes when carrying prey to the mouth and at times for locomotion.

Swimming: Power stroke executed by the cilia comprising each ctene is toward the aboral surface, so that the ctenophore swims mouth first. Musculature is not involved in swimming.

Digestive canals: extend off the top of the stomach to the anal pores at the aboral surface. Undigested waste is excreted through the anal pore.

Reproduction: simultaneous hermaphrodites possessing male and female gonads. The gonads are on the walls of the digestive canals and the gametes are freed into the digestive tract and discharged out through the mouth. The eggs are fertilized externally in the water. the embryos go through a cydippid stage where they are a miniature ctenophore with a pair of branched tentacles. As the larva develops into an adult, it loses the tentacles and metamorphosis is complete.

Bioluminescence: A chemical reaction in which excess energy is given off as light rather than heat. All ctenophores are bioluminescent. The function of bioluminescence is unclear but it is believed it may be involved in mate recognition, prey attraction and defense.

Habitat: Planktonic, floating back and forth with the tide and currents.

Range: Entire Atlantic Coast

Niche: Voracious Carnivores feeding on zooplankton

Personal Observations: When I first discovered Leidy’s comb jellies caught in my minnow trap, I thought it was some kind of slime. My husband said “We live on a river of slime”. At some point though we put some of this “slime” into our aquarium and it started to swim! At night, when I catch the comb jellies with my net they display intense bioluminescence, making me think they are using this as a defense. Comb jellies do not last long in captivity as they are quite fragile. Catching them is difficult as they will be hurt by a net. If you can, try and capture them using a wide-mouthed jar. In captivity they will feed on brine shrimp or minute amphipods in a tank.