1 54 Phylum Plathelminthes 



dams, in the riffles of streams, or on wave-washed shores of lakes. If 

 such waters are not frozen over, collections may often be made in mid- 

 winter. Stones or boards should be removed from the water and the 

 lower surfaces examined for planaria. When found in suitable numbers 

 scrape the worms off into dishes or pails of water, or bring in the small 

 stones with worms adhering. 



Planaria may usually be secured in considerable numbers by bringing 

 in masses of submerged vegetation. Cover this material with water, 

 preferably pond water or untreated tap water in large glass jars or 

 aquaria, and allow decay to start. The worms will collect on the surface 

 of the water and on the sides of the vessel. Transfer them to finger 

 bowls or larger vessels of clean water, and keep the dishes in a darkened 

 place. 



Feed planaria on tubificid worms, giving only as many tubificids as 

 will be eaten in 3 or 4 hours. Since these worms are completely ingested 

 and live until eaten, the dishes need not be cleaned as frequently as when 

 liver is fed. Dishes should be washed once or twice a week, but soap and 

 other chemicals must be avoided. 



References 



For the culture of planaria see also p. 142. 

 For the culture of triclads see also p. 136. 



PLANARIANS 



Libbie H. Hyman, New York City 



Collection. Different species of planarians live in different sorts of 

 habitats. Some, notably our most common species, Euplanaria macu- 

 lata, live in ponds, lakes, and the slow parts of rivers on the vegetation 

 and on the under surface of stones, leaves, or other objects. They may 

 be obtained by turning over stones and fallen leaves and washing the 

 animals into a pan by means of a strong squirter made of an atomizer bulb 

 and glass tube. Their presence on vegetation may be ascertained by 

 shaking small samples of the vegetation in a vessel of water. If they are 

 present large quantities of the vegetation should be gathered and placed 

 in pans with a small amount of water. As planarians cannot endure 

 stagnant water, they soon come to the top and may be picked off. 



Other species, notably the large dark forms such as Euplanaria agilis 

 and E. dorotocephala, live in springs and spring-fed streams and marshes. 

 Their presence may be discovered by baiting a suspected habitat with a 

 piece of raw meat placed along the edge, not in the current. After 15 or 

 20 minutes, the piece of meat should be turned over and planarians, 

 if present, will be found attached to the under side. The entire habitat 

 should then be baited with meat. Fresh raw beef is best and should be 



