long, tube-like pharynx can be protruded to take in particles of food. The 

 digestive tract extends into all parts of the body and has either three main 

 branches, one anterior and two posterior to the mouth, or else a modification 

 of one large sac, which may divide into a complex arrangement of many small 

 branches. These branches can often be seen through the body wall, especially 

 if they are distended with food of a color different from that of the body. 



The Turhellaria show extreme powers of regeneration. One of the com- 

 mon genera, Dugesm, has been widely used in experimental laboratories. Dr. 

 Child has shown that even a fragment consisting of as little as one-two hundred 

 and fiftieth of the original animal can still replace the missing parts and form 

 a complete animal. In its natural state the creature frequently breaks into two 

 of its own accord, and each part regenerates the portions it lacks. Eggs are also 

 produced at certain seasons of the year. 



Until recently the larger Turhellana of Europe and America were sup- 

 posed to be very closely related, if not actually the same species. Studies of 

 their internal anatomy now seem to indicate that there are important differ- 

 ences. The familiar name Planaria is now reserved for European forms, and 

 our American forms are called Dugesia or other new generic names. 



The Tslemathelminthes or Round Worms have neither the gliding motion 

 of the flatworm nor the segmentation of the ringed worm. Their motion is 

 snake-like, their form thread-like. The tiny or microscopic members of the 

 group have received the popular appellation of ''nemas". The nemas most widely 

 known, until modern methods of merchandising developed, were the "vinegar 

 eels". As a matter of fact, nemas are universally present almost everywhere 

 life of any form can exist, from arctic ice to tropical jungles. They are often 

 parasitic on plants and cause damage in greenhouses and nurseries. 



Another famous member of the Round Worm group is the Horsehair 

 Snake. Many a farm boy has seen these undulating "'serpents"''' swimming in 

 the watering trough and has never doubted that, in some miraculous way, 

 some hairs from Dobbin's tail have become endowed with life. It is a pity 

 that Gordnis (Linnaeus named the animal after the classic Gordian knot which 

 even Alexander could not untie) has no press agent of his own, for his true 

 life is even more remarkable than his legendary one. Starting his career as 

 a parasite in the intestine of some insect, commonly a grasshopper, he travels 

 a la Jonah all summer and finally, leaving his dying host, he emerges for a free- 

 living adult life in some pond or stream. Really quite common in our smaller 

 bodies of water, the little Gordian knot progresses very slowly and, if noticed at 

 all, is mistaken for a fine rootlet moving with the current. 



The larger and usually terrestrial members of the Annelida or Ringed 

 Worms are familiar to all of us, if only in the form of fish bait or as prey for 

 the robins on our lawns. In addition, there are hosts of smaller and more 

 active ones in the ponds and streams. The worm as we usually meet him is 



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