Radiates- Phylum Cnidaria and Ctenophora

Radiates

Phylum Cnidaria 

• Have Nemocysts 
• Mostly marine and all aquatic 
• 2 forms; sessile polyp and free swimming medusa 
• More than 9,000 species 
• Have radial symmetry
• Reproduction: sexual (hermaphrodite- gamtes into water --> free larva) and asexual (budding)
• Have 2 germ layers- epidermis and gatrodermis
• Use tentacles and nemocysts to catch food
• No excretory or respiration systems
• Tissue types; nerve,muscle and epithelium but NO connective tissue 
• Habe gastrovascular cavity- for digestion and gas exchange
• Nervous system; mechanoreceptors, photoreceptors and chemoreceptor- no central nervous system- 2 nerve nets at base of epidermis and gastrodermis
• Have 4 major classes within this phylum;
• Class hyrozoa …