MOVEMENTS, KTC, OF FRESM-WATEli PLANARLINS. 517 



extremity ofteu, and moved it to and fro as if to feel 



or see its way." " When the anterior extremity of the body 

 was cut off the remainder of the animal seemed still to move 

 with definite purpose^ avoiding* obstacles and retreating from 

 the lightj while the cut end was raised and thrust in various 

 directions as if to search for an object on which to climb." 



In a brief note Zacharias ('88) mentions the occurreuce of 

 Geodesnius terrestris between the lanielh\3 of Agaricus 

 deliciosus. Particular points mentioned are : the slow 

 movement, characterised by the raised anterior end, and the 

 hanging by a mucous thread after passing over the edge of 

 a glass plate. Light stimulation of the anterior end with a 

 needle induces a very strong contraction of the whole body. 



Gamble ('03), in a systeuiatic paper on marine Turbel- 

 laria, describes briefly the movements of a number of 

 species of rhabdocoeles and triclads. 



Lang ('84), in his monograph ou the jiolyclads, devotes a 

 chapter to the habits, movements, and natural history of this 

 group of planarians (loc. cit., pp. Goi — G41). While not 

 done particularly from the physiological standpoint and not 

 treating the subject experimentally, tliis work contains 

 numerous valuable observations. Points especially treated 

 are the habitat, colouration, food and method of feeding, 

 defecation, movements, including swimming, copulation, 

 respiration, regeneration, growth, and duration of life. The 

 details in the behaviour of the polyclads recorded in this 

 monograph will be discussed later in connection with the 

 points on which they have direct bearing. 



The most important paper dealing with the movements 

 and general behaviour ot" planarians which I have been able 

 to tind in the literature is that of Lehnert ('91). Tiiis work 

 is principally devoted to an account of the biology of three 

 forms of land planarians, viz. Bipalium kewense, B. 

 kewense var. viridis, and Geodesnius bilineatus. 

 Besides the work on these land forms, Lehnert also made 

 some comparative studies on several fresh-water dendrocuolcs 

 and rhabdocoeles. He gives an admirably full and detailed 



