The main difference between sponges and cnidarians
What are tissues?
100
A 20-meter-long bioluminescent colonial animal preferring colder waters that looks like a tube that's open on one end and closed on the other
What is a pyrosome?
100
Mostly sessile echinoderms
What are the Crinozoa?
100
Tiny freshwater cnidarian that reproduces by budding
What is a hydra?
200
Deep-water animals with no tissues that have a skeleton made of siliceous spicules; some scientists consider them to have their own phylum for one class
What is Hexactinellida?
200
Body part all chordates have in embryonic stages and (mostly) lose later on
What is the notochord?
200
The slightly smaller cousins of pyrosomes
What are salps?
200
Close relatives of sea stars with longer, more flexible arms and a rounded pentagon for a body
What is a brittle star?
200
Class of gelatinous, motile cnidarians with developed eyes
What are the Cubozoa?
300
Extremely rare reef consisting of only tissueless animals
What is a sponge reef?
300
Opening that forms first in protostomes
What is the mouth?
300
Non-vertebrate chordates other than tunicates
What are the Cephalochordata?
300
Order of unusual deep-sea starfish containing only one genus
What are the Peripodida?
300
Group of microscopic, obligately parasitic cnidarians
What are the Myxozoa?
400
World's only order of freshwater sponges
What are the Spongillida?
400
Symmetry of cnidarians that differentiates them from bilaterians
What is radial symmetry?
400
Sessile tunicates
What are sea squirts?
400
Unusual echinoderm that looks like a tube
What is a sea cucumber?
400
Species of 50m deep-sea siphonophore
What is Praya dubia?
500
Phylum of tissueless animals containing only ONE species in the entire phylum
What is Placozoa?
500
Where echinoderms are classified despite their apparent radial symmetry
What is Bilateria?
500
Neotenic tunicates
What are the Larvacea?
500
Order of primitive sea urchins with widely spaced, thick, blunt spines
What are the Cidaroida?
500
Order of jellyfish-like cnidarians that have stalks and have the tentacles up rather than down