Knowledge of the Amoebge. 107 



from the Frankfurt aquarium. But this spring I brought 

 with me some bottles of sea-water with living contents from 

 the Baltic coast and from the harbour of Genoa, and mixed 

 this with the rest, so that I am bj no means in a position to 

 furnish the habitat of the creature that will here be described. 

 The marine Protozoa, or at anj rate those of the coast-tauna, 

 seem, however, to be tolerably cosmopolitan ; and we maj 

 therefore assume for Amceba tentaculata a wide distribution in. 

 our seas*. If I beat fragments of a seaweed upon the object- 

 slide, or scraped off a little of the crust deposited on the glass 

 wail of the aquarium, some specimens of the Amoeba almost 

 always made their appearance. 



It forms a little mass of very variable size. The smallest 

 examples measured about 0*03 millim., the largest 0*12 millim. 



In consequence of its greater refractive power, the body 

 stands out luminously from the water, a property which, 

 in the protoplasm of all Rhizopoda, goes hand in hand with 

 greater viscosity. Here also we find the rule confirmed j for 

 the protoplasm of Amoeba tentaculata is, in fact, an extremely 

 tenacious mass, in comparison with that of allied creatures. 



Under a low power (about 80 diameters) we can see no 

 movement or change of form in the animal j and it is only 

 when we employ high and very high powers that we can 

 convince ourselves that we have before us an Amoeba the 

 form of which is engaged in a continual although sluggish 

 change. We shall soon see that the apparently motionless 

 animal is really capable of locomotion, and may pass into a 

 flowing state, distinctly recognizable under high powers. 



But if we first of all examine the creature in the resting 

 state, in which it generally is when it has not long been 

 placed on the object-slide, the Amoeba has then essentially the 

 same form as aw Amceba verrucosa -, i. e. the whole body is, as 

 it were, shrunk together, with its surface covered with elevated 

 knobs and deep folds, which slowly change their form and 

 position. 



In the interior the vital activity of the protoplasm is mani- 

 fested by a streaming and trembling movement of the fine 

 dark granules with which the sarcode is abundantly fur- 

 nished. 



80 far there would be nothing remarkable to observe in the 



* Last spring I found my Cothurnia opiixulata (Zeitschr. f. wiss. Zool. 

 Bd. xxviii. ) in the harbour of Genoa, whilst tlie former examples were 

 derived from the Frankfort aquarium, and therefore from northern seas. 

 The same aquarium also contained Cothurnia svcialis, referred to as cited 

 above ; and this I quite recently discovered in abundance upon fragments 

 of Hydrozoa brou"Jit from the Baltic. 



8* 



