Planariidae 155 



cut into pieces 1 or 2 inches wide and 2 or 3 inches long. Such pieces 

 should be distributed throughout the edges of the habitat so as to rest 

 partly in the water, partly above the water. At intervals of 15-20 min- 

 utes the pieces should be picked up with a long forceps and shaken off 

 into a jar of water. With a few trials of this sort the best spots in the 

 habitat are soon discovered and all of the meat may be moved to such 

 spots. In preparing such collections for transport back to the laboratory, 

 they should be washed free of bits of meat by several rinsings, and the 

 jars filled not more than % full with fresh clean water from their habitat. 

 A depth of not more than an inch of planarians should be allowed 

 to a pint jar. In bringing them in, care must be taken to avoid high 

 temperatures. The jars must not be set on the floor of a car which is 

 apt to become hot from the engine. 



Baiting with meat is usually ineffective with pond habitats and com- 

 monly succeeds only with species which live in flowing water. Some 

 species, however, even in flowing water, respond poorly to this method 

 and must be picked from stones and water weeds by hand. Among the 

 species which the author has personally seen or knows may be collected 

 successfully by baiting are: Euplanaria agilis, E. dorotocephala, Fonti- 

 cola velata, and Phagocata gracilis. Euplanaria maculata and Procotyla 

 fluviatilis usually respond poorly to meat baits. 



Laboratory maintenance. Planarians of practically any species may 

 be kept successfully in the laboratory in glass or crockery containers or 

 enameled pans. These should be darkened by means of suitable covers. 

 Treated city waters are not very suitable, but most species will live in 

 such water for a considerable time. Spring or well water is desirable. 



Those species mentioned above as collectable by baiting with meat are 

 also the ones which may be kept most easily and successfully in the 

 laboratory. They are fed two to three times a week on beef liver (pig 

 liver is not suitable). Before feeding, the water in the pan should be 

 lowered to a depth of several inches. The liver should be cut into long 

 thin strips and disposed over the bottom. The pan is then covered 

 and left undisturbed for 2 or 3 hours, after which the liver is removed, 

 the pans thoroughly rinsed, and filled with fresh water. Even if the 

 animals are not fed, the water should be changed two or three times 

 weekly as planarians are very susceptible to fouling of the water. All 

 food fragments should be carefully removed. E. dorotocephala, E. agilis, 

 and Curtisia foremanii are very easily kept by this method for long 

 periods of time in the laboratory; Fonticola velata and Phagocata gracilis 

 may also be maintained on liver, although not so well as the first-named 

 species. In place of liver, pieces of earthworm, clam, etc., may be used; 

 some forms prefer such food. Yolk of egg drawn out with a dropper 

 into a strand on the bottom has been employed successfully. 



