GENUS AMCEBA— AMCEBA PROTEUS. 49 



enclosure. The nucleus and contractile vesicle exhibit the usual charac- 

 ters and relative position, as in more common forms of Amoeba proteus. 



An individual of the kind just described I had the opportunity of seeing 

 swallow and digest one of another species, the Amoeba verrucosa. The steps 

 of the process I have attempted to represent in figs. 13-19, pi. VII, and 

 they occurred as follows : 



In a drop of water squeezed from mud adhering to the roots of the 

 plant Ludwigia, collected in a half-dried marsh, in the month of August, I 

 noticed an active Amoeba, as seen in fig. 13. It was of elongated triangu- 

 lar, snail-like form, with the anterior broader extremity extended into a 

 number of conical antenna-like pseudopods. The posterior end was some- 

 what coarsely papillose, and from the left side projected two conical pseudo- 

 pods like those in front. Observing an Amoeba verrucosa, fig. 12, in its usual 

 sluggish condition, lying almost motionless, directly in the path of the 

 former, I was led to watch whether the two would come into contact and 

 what would be the resnlt. 



The A. proteus contained a number of large food- and water- vacuoles, 

 together with a single diatom. The contractile vesicle occupied the usual 

 position and exhibited the usual changes. The A. verrucosa, besides the 

 granular protoplasm, appeared to contain nothing but a conspicuous con- 

 tractile vesicle, and this remained unchanged. 



The snail-like Amoeba reached the A. verrucosa, and turning with tail 

 end towards the right, the body shortened, and a pair of digitate pseudopods 

 extended from the head and embraced the latter in the manner represented 

 in fig. 14. The conjoined ends of the pseudopods fused together, and the 

 animal reversed its direction of movement, while the A. verrucosa gradually 

 sank deeply within its body, and assumed the appearance of a large 

 sphere, still retaining its contractile vesicle unchanged, as represented in fig. 

 15. The snail-like A. proteus assuming nearly the original shape, as first 

 not iced, then moved about after a while and presented the appearance 

 seen in fig. 16. The tail end of the body was elongated and papillose, and 

 the swallowed Amoeba, reduced in size, had lost its contractile vesicle 

 and become oval in shape. Later, the A. proteus appeared more slug- 

 like, while its victim had become pyriform and striate, and was then 

 included within a large water-vacuole, as represented in fig - . 17. Subse- 

 quently, the A. proteus was observed to discharge the diatom, previously 



4 KHIZ 



