1913] Gee : Behavior of Leeches 245 



which they left. This is not at all impossible, but is, I believe, 

 more likely to be the result of accident rather than any selective 

 action for a certain parent on the part of its yoiing. 



4. Operation Experiments 



The anterior ends of a couple of dozeiLS of specimens of Dina 

 microstoma were removed at various distances along the body 

 length. These operated specimens were allowed four or five days 

 for recovery from the shock effects of the decapitation before 

 experiments were conducted on their behavior. Observations 

 at this time showed little difference, except for vigor, in the 

 character of responses as contrasted with that five months later. 

 Loeb (1894) states that he has kept operated leeches for a year 

 without regeneration : ' ' Schneidet man einen Blutegel in der 

 Mitte entzwei, so zeigen die beiden Stiicke durchaus versehiedene 

 Realrtionen. Die Wunde heilt sehr bald und die Stiicke konnen 

 ein Jahr und langer leben, ohne dass jedoch, wie bekannt, irgend 

 welche Regeneration stattfindet." Morgan (1901) says with re- 

 gard to regeneration in leeches: "A leech is not much more 

 complicated than a marine annelid, yet it has little or no power 

 of regeneration." Gluschkiewitsch (1907) states in a prelimi- 

 nary report that he finds in the young of Clepsine {Glossiphonia) 

 tessulata a regeneration of both the anterior and posterior ends. 

 Adult specimens were not used in the experiments, and this fact 

 may afford the basis of the difference between his results and 

 those of other workers. He says: "Nach 23 Tagen waren unter 

 den am Vorderende amputierten Individuen drei vollstandige und 

 fiinf unvollstandige Regenerate zu sehen. " Hirshler (1907) 

 found from sections of operated adult specimens that regener- 

 ation to a slight degree occurred in Nephelis, Clepsine {Glossi- 

 phonia), and Hirudo. The process, however, amounted to little 

 more than a wound closure. 



Although regeneration was not made the subject of any series 

 of experiments, some observations were incidentally noted in 

 this regard. Many of the specimens decapitated have continued 



