i 



1 



t 



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Dr. A. Grubsr on Protozoa. 273 



On one side of the individual figured (fig. 4) a second 

 smaller one is seen to be attached ; it is in process of fusion 

 with the larger one, just as we shall observe hereafter in Acti- 

 nophrys. Here only the endoplasm, t. e. the nutritive paste, 

 was, in the first place, absorbed by the larger Rhizopod. The 

 whole of the brown contents of the smaller individual flowed 

 in a slow but constant stream into the larger one, so that finally 

 there remained of the former only a clear mass of protoplasm, 

 rich in vacuoles, but destitute of any nutritive particles, and 

 from which also the pseudopodia had disappeared. 



So long as I could observe the two specimens no complete 

 fusion had taken place ; but remarkable changes occurred in 

 the larger Rhizopod. It entirely lost its regular form. The 

 brown contents became balled together in several masses ; the 

 outer layer dissolved, so that in some places there remained 

 only a fine zone which was pushed outwards by large vacu- 

 oles ; in short, the form of the whole creature became exceed- 

 ingly irregular, as if it were about to break up. Soon after- 

 wards, however, it gradually approached the original form, 

 which it finally almost completely resumed. 



From this we see how little constancy there is in the sepa- 

 ration into two regions in the Rhizopoda, and how easily 

 plasmas temporarily appearing separated may become mixed 

 together. The changes which have taken place in one and 

 the same individual also furnish an indication why the forms 

 here under consideration may be so different in respect of the 

 structure of their protoplasm.' 



The behaviour of the pseudopodia is very remarkable. They 

 do not issue as simple processes from the outer layer of proto- 

 plasm, but come forth as fine rods of uniform thickness from 

 a cone of hyaline sarcode, exactly in the same way that I 

 have recently described in the case of Amoeba tentaculata* . 

 Here also the filament issues exactly from the apex of the 

 cone ; and when it is again retracted, there always remains a 

 small cup-shaped depression. The pseudopodial cones, how- 

 ever, are usually much more numerous than in Amoeba tenta- 

 culata, and also generally arranged with remarkable regu- 

 larity (fig. 4). 



In the above-mentioned Amoeba the whole body, including 

 the pseudopodial cones, appeared, under a high power, to be 

 surrounded by a distinct double contour, which is not the case 

 here, or, at least, could not be observed in by far the greater 

 number of cases. Nevertheless here also, as in Pachymyxa, 



* "Beitrage zur Kenntniss der Amoben," Zeitachr. fur wiss. Zool. 

 Bd. xxxvi. 



Ann. & Mag. N. Hist. Ser. 5. Vol. xi. 19 



