Class Scyphozoa

(jelly fish)

Major Attributes:

Radial symmetry.
Marine habitat.
Dominate medusa stage.
Short or long tentacles with nematocysts.
Mostly free-swimming, but some sedentary.

Description:
Generally 6-12 inches or more in diameter, scyphozoans have scalloped rims and a complex pattern of digestive canals seen within the medusa. Medusae can be identified by the absence of a vellum within the margin of the bell. The mesoglea is thick and firm and contains wandering amoebocytes. Most medusae are carnivorus, but some are filter feeders, including Aurelia. Reproduction can be sexual or asexual.

Some Interesting Facts:

The giant Red Jelly found in Artic waters can be 8 feet in diameter with tentacles extending 200 feet.
Many scyphozoans can inflict painful stings and should be avoided by swimmers.
The polypoid stage is an inconspicuous organism called scyphistoma. This stage is lacking in some species.

Some Pertinent Books Found in Lamson Library:

Buchsbaum, Ralph. 1976. Animals Without Backbones. Chicago: University of Chicago.
Hengner, Robert W. and Joseph G. Engemann. 1968. Invertebrate Zoology. Toronto: Macmillian Company.

(Dana L. Andrews)(edited by B.J. Miller)