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Chapter III 



MARINE ANIMALS THAT STING 



INVERTEBRATES 



Venomous marine invertebrates, or marine animals without 

 backbones that inflict their injuries by stinging, can be grouped 

 into four major categories: 



1. Coelenterates 



2. Molluscs 



3. Annelid Worms 



4. Echinoderms 



— Hydroids, Jellyfishes, Corals, and 



Sea Anemones 

 — Univalve shellfish, and Octopuses 

 — Stinging or Bristle Worms 

 — Sea Urchins 



Coelenterates 



The coelenterates, which includes the hydroids, jellyfishes, corals, 

 and sea anemones, are simple, many-celled organisms. In addition 

 to a number of other technical characters, they all possess tentacles 

 equipped with nematocysts or stinging cells. It is these stinging 

 cells which make them of interest to the skin diver. 



The coelenterates are divided into three principal classes : 



I. Hydrozoa: the hydroids. To this class belong the hydroids 

 which are commonly found growing in plume-like tufts on rocks, 

 seaweeds and pilings. Some of the more common stinging mem- 

 bers of this group are the following : 



Stinging or Fire Coral, Millepora alcicoimis Linnaeus (See 

 Frontis.). This false coral is generally found living among true 

 corals along reefs in the warm waters of the tropical Pacific, Indian 

 Ocean, Red Sea, and Caribbean Sea. 



Portuguese-Man-O'-War or Blue Bottle, Physalia physalis 

 (Linnaeus) (Frontis). This hydroid is most commonly mistaken 

 for a true jellyfish. Actually, it is a colonial hydroid. It is almost 

 always found floating at the surface of the water. Suspended from 

 the balloon-like floats are the stinging tentacles which may trail sev- 

 eral feet down into the water. This particular species inhabits the 

 tropical Atlantic, going as far north as the Bay of Fundy, the 

 Hebrides, and the Mediterranean Sea. A closely allied species is 

 found in the Indo-Pacific area, Hawaii, and southern Japan. 



II. Scyphozoa : The true jellyfishes. This class includes the 

 larger medusae, having eight notches in the margin of the bell. 



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