102 PROFESSOR O. BiirsCHLI. 



a homogeneous mass of tolerably high refractive index. The 

 author then goes on to describe the way in which these 

 masses are produced by the various movements of the proto- 

 plasm. The filiform structure of the Amoeba disappears after 

 the application of such pressure to the cover glass as will 

 kill the organism, at the same time the protoplasm becomes 

 homogeneous. This phenomenon is due, the author states, 

 to the fact that the threads of protoplasm swell up under the 

 pressure, take up the fluid, and fuse with one another. lu 

 this Amoeba, the protoplasm on the surface of the body 

 sometimes becomes homogeneous during the execution of 

 moderately active movements, sometimes travelling over the 

 surface as a hyaline seam of greater or less extent, whilst 

 sometimes short and bluntly conical pseudopodia arise. The 

 formation of such pseudopodia, however, is rare. 



Inside the body are the food particles in greater or less 

 numbers, ♦he nature of which has not yet been made out. 

 Contractile vacuoles have been several times observed, they 

 were numerous, and arose upon the surface of the body in a 

 semicircle, uniting at the period of contraction. 



The nucleus is usually large and oval, 0"018 — 0"02 mm. 

 in diameter in a moderately large specimen (fig. 26, a, ?i). 

 It consists of a very large thick and dark case which is 

 apparently homogeneous (fig. 26, b, h). Within this case 

 are finely granular, reticulated contents, which surround a 

 sheath probably filled with fluid. Within this sheath a dark 

 corpuscle is sometimes seen, and round it is a delicate mem- 

 brane. It is remarkable that these nuclei often appear dis- 

 tinctly pointed at one end, or have a neck or knob-like 

 prominence (fig. 26 c), a peculiarity which, so far as the 

 author knows, has not yet been observed in any other 

 nucleus. Occasionally two nuclei are found in a single 

 individual, but this frequently happens in other Amoebae. 

 There has also been found an individual with four round nuclei 

 of the same size, 0"0086 mm.; further, one with eight nuclei, 

 0*007 — 0'0086 mm.; and one with fourteen nuclei, 0"006 — 

 00072 mm. These individuals with numerous nuclei are 

 not so large as the organisms with one or two nuclei. The 

 smaller nuclei were spherical, as is the case with the smaller 

 nuclei in Amoeha princeps. Two examples were found with 

 numerous nuclei, the one with six, the other with nine, in 

 which some of the nuclei departed from the round form, lu 

 the first example tliree of the nuclei were irregularly elon- 

 gated, whilst in the second, seven were drawn out into 

 spindles. The small nuclei differ in their construction from 

 the large ones, in that the space filled with fluid is in the 



