552 



S. M org III IS 



which justifies Biilow's question — "ob denn alien Thieren mit 

 irgend welchen regenerirten Enden die einst verlorenen Stiicke 

 von Feinden abgerissen seien, um als deren Nahrung zu dienen, 

 oder ob nicht etwa der Lumbriculus bei seiner eminent weitge- 

 henden Regenerationsfahigkeit sich selbst verstiimmelte, d. h. in 

 Stiicke reisse oder zerfalle um aus diesen Stiicken ganze Thiere 

 entstehen zu lassen und auf diese Weise durch einfache Querthei- 

 lung, also ohne vorher angelegte Knospungszone, sein Geschlecht 

 fortzupflauzen." 



Billow decides the question in favor of the latter possibility. 

 Miiller, as we have seen, is inclined to give a similar interpretation. 

 On the other hand this general view is disputed by some observers. 

 Thus DifFenbach accounts for the breaking up as the result of the 

 attacks of enemies. In order to throw some light upon this ques- 



TABLE I 



tion, i.e., to test whether the breaking up is merely a case of "reflex 

 throwing off of parts of the body, or autotomy,"'' or whether it is to 

 be looked upon as a normal process of reproduction, the following 

 observations were made. 



I found that in the American form of Lumbriculus there is lack- 

 ing the high degree of sensibility described by almost all students 

 of the European form. Worms kept in any kind of a dish, in the 

 presence or absence of mud, never broke up into pieces. Draw- 

 ing them into a pipette, and then spurting them out in a strong 

 current of water, repeated many times in succession, never caused 

 them to break apart in any way; nor did they react when put out 

 on a paper or in the palm of my hand. To be sure, care must be 

 taken not to injure the extremely delicate body-wall of the worms. 



^ Prof . T. H. Morgan: Regeneration, p. no, 1901. 



