236 University of California Puhlications in Zoology [Vol. il 



leech crawled by them or over them with entire disregard. In 

 cases where the parent was left in the dish with the eggs for 

 sixteen hours, and in one case for four days, not a single egg was 

 picked up or the mass of eggs brooded over, even when placed 

 in the least lighted portion of the dish. The stimulus of the 

 removal of the eggs caused at first a marked activity, but later 

 the animal was restored to the normal rate of activity, and even 

 then the eggs were as markedly disregarded as if they had been 

 debris in the dish. Thus the entire neglect of its eggs on the 

 part of the parent was several times proved distinctly. 



In other specimens with eggs attached, a part of the mass 

 was loosened up so that a few of the eggs dropped out and many 

 of them were hanging to the body. The only response was a 

 more contracted condition of the body in the region where the 

 eggs were carried. In this case there was also an acceleration 

 of the activity due to the stimulus of the removal of the eggs. 

 The local stimulation of the part of the body from which the 

 eggs were partially removed may satisfactorily explain the local 

 contraction of the body at this point. Although observed at 

 intervals of a few minutes for four hours, no reactions other 

 than this local contraction and initial acceleration of movement 

 were observed, and these conditions became normal within a half 

 hour after the experiment was begun. The carriage of the eggs 

 is to be viewed as a more or less forced condition on the part 

 of Glossiphonia stagnalis, due to the fact that they are enclosed 

 in sacs attached to the body. 



When the eggs are hatched the young are carried in much 

 the same place as the eggs. These young individuals are strongly 

 attached by the posterior sucker of their bodies. Removing the 

 young produces, as in the case of the removal of the eggs, an 

 active condition of the animal which seems to be entirely due 

 to the mechanical stimulation of removal, since the specimens 

 become normal in their responses after a period of a few minutes. 



Into a small dish 3 cm. in diameter were placed an adult 

 Glossiphonia and its detached young. The small leeches are very 

 quick to seize the opportunity of attachment, and often cling 

 to various parts of the body of the parent species. Upon their 

 attaching themselves to the dorsal surface of the body, particu- 



