104 



UNDERWATER GUIDE TO MARINE LIFE 



Fig. 32. Comb jellies. Adapted from Mayer (I9i2). 



On the West Coast is found the sohtary coral Balenofhylla, which reaches a 

 half-inch in diameter. 



COMB JELLIES: Phylum Gtenophora {"comb-bearer")— Figure 32 



There are only a few species of these exceedingly beautiful animals, but 

 these often occur in tremendous numbers and are common in all seas. Their 

 transparent bodies shimmer with delicate colors of glassy, iridescent beauty 

 and bear eight comblike rows of cilia which move the animal through the water 

 and have given these animals their name. 



Ctenophores are exclusively pelagic, predatory animals. They catch planktonic 

 prey or small fish by means of two long retractile tentacles that extend from 

 the sides of the body and which bear sticky "lasso cells." Some have no tentacles 

 and filter plankton from the sea. 



Almost all the species have very wide distribution. The little sea gooseberry, 

 Pleurohranchia, is found in all the seas of the world. The sea walnut, Mnemiop- 

 sis, is like the sea gooseberry, but it is larger and is luminescent. If a boat is 

 driven through a swarm of them, the disturbance causes each one to emit a 

 bright, sudden flash of light. The Venus girdle, CesUis, is very different from 

 these, being elongate and like a ribbon. It reaches a length of 3 feet occasionally 

 but is usually seen much smaller. 



FLATWORMS: Phylum Platyhelminthes— F/^wr^ 33 



Flatworms are not common or prominent in the sea, but are very well known 

 as parasites— the flukes and tapeworms. One group of small flukes, the schisto- 

 somes or blood flukes, has a larva that normally infects sea birds. It is also able 

 to burrow partially into human skin, where it forms an extremely itchy swelling 

 known as "swimmer's itch" or "seabather's eruption." These larvae die soon 

 after entering the swimmer's skin, so do not produce parasitic infection in man. 

 Phillips and Brady (1953) suggest immediate fresh-water bathing plus applica- 

 tion of dilute ammonia or antihistamines for relief of the itching. 



Not all flatworms are parasitic. The turbellarians are flattened, frequently 

 leaflike worms that creep about among plants or over the bodies of marine 

 animals such as crustaceans. They possess amazing powers of regeneration. If the 

 head of a turbellarian is cut off, the headless body grows a new head, and 



