e.g. Proootyta fZuviatitis and some subterranean planarians, apparently 

 do not react to chemical food stimuli but rather to vibrations produced 

 by their living prey, such as small crustaceans and insect larvae. Other 

 methods of securing deep-water planarians are by means of a bottom grab 

 sampler or by a trawling dredge equipped with a canvas bag which skims 

 the upper layer of mud or silt; the planarians may be separated by using 

 sieves of proper mesh size. 



TRANSPORTING AND CULTURING 



Some species of planarians can be indentified by an experienced collector 

 with reasonable certainty in the field. In many cases, however, it is 

 necessary to transport them to a laboratory or even to send them, 

 preferably alive, to a specialist. As many planarians, particularly 

 those living in cold springs, deep lakes, or in subterranean habitats 

 (caves, groundwater), are very sensitive to temperature fluctuations 

 (stenothermic) , they should be transported in well-insulated containers. 

 Vacuum- insulated (thermos) bottles are quite appropriate and may be used 

 also for the shipping by air mail (special delivery) across the continent, 

 provided they are taken care of immediately at the point of destination 

 (they should not arrive at a laboratory on a weekend) . 



Some planarians cannot be identified by their external features alone 

 but require the study of anatomical characters, specifically an analysis 

 of their reproductive organs. Unfortunately, many of the specimens col- 

 lected in the field are sexually immature. It is important, therefore, 

 to select the largest individuals from a given population for further 

 study and identification. Should there be no mature animals available, 

 it is often possible to raise young animals to maturity in laboratory 

 cultures. 



Culturing is carried out in shallow glass aquaria (finger bowls) or in 

 enameled pans kept in the dark or in dim light at proper temperatures, 

 according to the tolerance limits of the species. The water should be 

 changed every two or three days when kept at room temperature and about 

 once a week in refrigerated cultures. Spring water or filtered pond 

 water may be used, but chlorinated tap water should be avoided unless 

 the chlorine has been removed by appropriate chemicals (e.g., sodium 

 thiosulfate, the photographic "hypo"), by letting it stand for 24 hours 

 in an open container, or by bubbling air through it. The planarians may 

 be fed once or twice a week. Most species will accept small pieces of 

 liver, meat, clotted blood, cut-up earthworms, or living food such as 

 the oligochaete Tubifex (obtainable in pet stores as fish food). A few 

 species refuse dead food but attack living small crustaceans {GammcccuSt 

 Asellus^ Daphnia, etc.). The food is left in the aquarium for several 

 hours, then removed, the water changed, and, if necessary, the aquarium 

 cleaned. Planarians are capable of surviving extended periods of 

 starvation, several months, particularly when kept at low temperature. 

 When starving, they gradually grow smaller, their anatomical makeup is 

 simplified, their entire reproductive system is reduced, and they become 

 indistinguishable from young animals. 



