suggests segmentation. Most of what is known about 

 kinorhynchs has been learned from those along Eu- 

 ropean shores. Yet these animals have been found 

 on northern American coasts. Japan, Zanzibar, and 

 the Antarctic. They must be widely distributed. 



Kinorhynchs have no ciHa and cannot swim, but 

 crawl about on muddy or slimy bottoms, swallowing 

 fine debris. Some live on seaweeds, browsing on mi- 

 croscopic algae. To feed, the animal extends the 

 spiny, retractile head and protrudes a mouth cone 

 with a circlet of spines. Then it sucks in the food by 

 means of a muscular throat. Externally the males 

 and females cannot usually be told apart, but sex- 

 ual reproduction occurs at all seasons. The eggs hatch 

 into a larval stage. 



The Priapulids 



{Phylum Priapidida) 



This small phylum has, so far, only six species of 

 marine wormlike animals of dull color and moder- 

 ate size, the largest about 3 inches long. The cylindri- 

 cal and superficially ringed body, so warty that the 

 animal was once classed with the sea-cucumbers, has 

 a shorter front region which can be inverted and 

 withdrawn into the longer trunk region. The front is 

 well armed with rows of spiny teeth, for capturing 



prey as the worm plows through muddy bottoms. 

 Three species have long been known from northern 

 seas around the globe, down to 1500 feet (500 m.), 

 and as far south as Massachusetts and Belgium. One 

 of these, Piiapiihis caiulattis, or a form almost like it, 

 is found also in antarctic seas, as is another species 

 of the same genus. Until 1959 no priapulids were 

 known from middle latitudes; then a new species 

 was brought up from the cold bottom of the mid- 

 American trench, at a depth of nearly 17,000 feet, 

 ofl" the western coast of Costa Rica. 



The Horsehair Worms 



{Phylum Nematomorpha ) 



The horsehair worms have been known for many 

 centuries, and almost from the beginning have been 

 associated with the myth that they were animated 

 horse hairs, transformed after being dropped from 

 horses into bodies of fresh water or into drinking 

 troughs. The resemblance is not too far-fetched, for 

 these long, fine worms are often about 6 inches long 

 and black or brown in color, though the color may 

 be yellow or gray and the length may approach 3 

 feet. The diameter of the body ('4(i of an inch at 

 most) is almost the same throughout, though it ta- 

 pers very slightly at the rear and a little more at the 

 front end. Males are shorter than females and usu- 

 ally slightly curved at the rear. 



We no longer need a fanciful explanation for why 

 horsehair worms suddenly turn up, full-grown, in a 

 body of water that had none the day before. The lar- 

 val worms develop within the bodies of insects, usu- 

 ally land beetles, crickets, and grasshoppers. The 

 adults emerge full grown and make their way to wa- 

 ter. They have a degenerate digestive tract and never 

 feed. Though the males can swim slowly, the females 

 do little more than writhe about. 



In the springtime one may find writhing masses of 

 as many as twenty tangled worms, and this has given 

 rise to another common name, gordian worms, refer- 

 ring to the Gordian knot of the ancient Greek myth. 

 Only one pair of worms is involved in a copulation, 

 however, and the fertilized eggs are laid in long, 

 gelatinous strings. After hatching, the larva swims 

 about for a short time, then presumably encysts on 



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