THE MOVEMENTS AND REACTIONS OF AMCEBA. 147 



and its movements can be followed ; at times, also, objects actually 

 cling to the surface, as in the other species. 



The results are essentially the same as in the species already described ; 

 foreign particles resting upon or clinging to the upper surface are car- 

 ried forward to the anterior edge. Here they roll over the edge, passing 

 beneath the Amoeba, which now moves across them. As a rule in 

 these species particles do not cling to the surface after passing to the 

 lower side, so that they are left behind when the posterior end passes 

 over them. Sometimes they do thus cling, however, and in such cases 

 I have seen them pass upward at the posterior end and again forward, 

 exactly as in A. verrucosa and its relatives. In order that my state- 

 ments may not remain abstract and general, I copy a few observations 

 from my notebook, all relating to Amce.ba proteus. 



1 . A large particle of debris with bits of soot attached to it was seen 

 lying on the upper surface just behind the middle. It was carried 

 forward to the anterior end and over the edge. Then it came to rest 

 on the bottom, and the Amoeba crept over it till it was passed by the 

 posterior end and left behind. 



2. A number of soot particles on the upper surface just in front of 

 the middle were carried forward, changing their direction as the proto- 

 plasmic currents beneath them changed direction. They were finally 

 carried over the anterior edge. 



o 



3. A small mass of soot was lying on the middle of the upper surface. 

 It moved forward in the same way as the endosarcal granules under- 

 neath. The latter changed their direction of movement several times ; 

 the soot mass changed correspondingly at the same time. It was 

 finally carried over the anterior edge, where it could be seen clearly 

 separate from the Amoeba. 



4. A large mass of soot one-quarter the size of the Amoeba was 

 carried forward on the upper surface for a distance, but fell off at the 

 side before reaching the anterior end. 



5. Two small masses of soot lying on the upper surface of the 

 posterior end were carried forward over the anterior edge. 



6. Several small particles were clinging to the lower surface of the 

 posterior end. They passed upward, one of them around the very 

 middle of the posterior end, to the upper surface ; here they were 

 carried forward and over the anterior edge. 



I could add a large number of such observations. 



On the under surface the particles are quiet, as I have shown before 

 (p. 136). At the lateral margins the edges of this quiet lower surface 

 are seen, so that particles situated here are usually likewise quiet, until 

 they have reached the posterior part of the Amoeba (see p. 135). 



As to the details of the movement of the upper surface, the following 



