Cnidarian Dissection Moon Jellyfish • 1 minute video of moon jellyfish “in motion” • Moon Jellyfish – YouTube Oral arms vs. marginal tentacles • A jellyfish has many tentacles. Some hang around the bell of the jellyfish. These hold the stinging cells. Other tentacles hang around the mouth. These are called oral arms. They may or may not have stinging cells. The oral arms pass the food into the jellyfish’s mouth. The food then goes into the animal’s stomach. Rhopalium • Rhopalia (singular rhopalium) are the most obvious sensory structures of scyphozoan jellyfish. They include specialized structures for sensing light (eyespots) and movement or direction with respect to gravity (statoliths). Moon Jelly Moon Jelly Structures to identify • • • • • • • • • Bell epidermis Oral arms Tentacles Mouth Gastrovascular cavity Rhopalium Mesoglea gonads Dissection video • http://www.youtube.com/watch?v=IdhBRz2Yq 1Q Tentacle observation • Use a dissecting microscope Sea anemone Metridium information • http://www.boydski.com/diving/photos/metri dium.htm Metridium video • http://www.youtube.com/watch?v=AlNGccPE NGw • 1. Metridium fields • http://www.montereyscubaboard.com/metrid iumfields.php Sea anemone • Feeding: • http://www.youtube.com/watch?v=nI8A61uq ybw Sea anemone: Metridium Sea anemone dissection • External: basal (pedal)disk, tentacles, mouth • Internal: siphonoglyph, pharynx, septa (incomplete and complete), coelenteron, acontia, rector muscle, gonads Lab procedure • You will have step by step details for dissection • Questions/sketches will be completed in your journal and collected for a grade • Dissection quiz – Anatomical directions – Species information – Anatomy as seen in dissection