Comb jellies |
---|
|
Light refracting on comb rows of Mertensia ovum This one is damaged and asymmetrical, with right lower portion of body regenerating from damage. The body of this species is about 3 cm long. |
Scientific classification |
---|
Domain: | |
Kingdom: | |
(unranked): | |
Phylum: | Ctenophora
|
Classes |
---|
Tentaculata Nuda |
The phylum Ctenophora, the comb jellies, is a phylum of marine invertebrates. They are part of the plankton, and there are also pelagic species. The phylum includes the sea gooseberry (Pleurobrachia pileus) and Venus' girdle (Cestum veneris).
The phylum was grouped with Cnidaria (jellyfish) in the former Coelenterata phylum. Ctenophores are the most basal known type of animals.
Even though they look like jellyfish, they are zoologically not related to them. They lack the characteristic nematocysts (stinging cells), but have colloblasts, sticky cells that snare small victims. They have eight rows of cilia which look like the teeth of a comb, hence Ctenophore = comb-bearer. Ctenophores have connective tissues and a nervoussystem. There are about 150 described species of ctenophora spread throughout the world's oceans, from shallow estuarine waters to the deep sea.