268 Dr. A. Gruber on Protozoa. 



we often find whole layers of light points, which are due to 



such Rhizopods. One of the large specimens that have come 



under my observation measured 06 millim. in length, with a 



breadth of 0*3 millim. ; while, on the other hand, Pocky myxce 



may very often be met with of a globular form and not more , 



than # 09 millim. in diameter. When a specimen is placed 



under the microscope and examined by transmitted light, it no 



longer appears white, but brownish. 



What makes its appearance in the first place is nothing but 

 an envelope which surrounds the protoplasmic body of the 

 Rhizopod. This envelope consists of a layer of closely 

 approximated fine bacilli, which stand about perpendicularly 

 to the surface of the protoplasmic body ; they form a sort of 

 felt, or, more properly, a completely closed spiny coat. I 

 have not succeeded in ascertaining of what substance these 

 spines consist. In chromic acid they dissolve immediately, 

 while they remain entirely unaltered on the addition of osmic 

 acid, for which reason the latter reagent was always employed 

 when it was intended to make a permanent preparation. 



I had a notion that the spines might consist of carbonate 

 of lime, but could not succeed in confirming this supposition 

 by means of reagents. 



This much, however, is certain, that the bacilli are not 

 foreign bodies collected and fitted together, but are a pro- 

 duct of the protoplasm itself. On examining the surface, 

 we find that the coating is not completely closed, as it at first 

 appears, but that in many places the bacilli separate and 

 leave gaps between them. These are circular apertures, pretty 

 regularly distributed, which perforate the envelope. In fig. 1 

 the bacilli on the surface appear depressed and somewhat dis- 

 placed by the pressure of the glass cover, whilst at the periphery 

 they show themselves in their regular position. It might be ex- 

 pected that the pores would appear as gaps at the margin ; but 

 this is not the case, because here the pore is not sharply limited, 

 on account of the bacilli lying beneath it. 



These pores are seen both in the living animal and in the 

 empty envelope and the osmic acid preparation. They first 

 led me to the supposition that in these little masses I had 

 before me a Rhizopod which, perhaps, like a Foraminifer, 

 could emit pseudopodia through the pores of its envelope. 

 But the vital phenomena of Pachymyxa are so sluggish that 

 the animals when taken from the aquarium and placed on 

 the object-slide usually remain motionless in their envelope. 



I was already beginning to regard any further investiga- 

 tions with despair, when, to my delight, I met with a speci- 

 men from which a number of pseudopodia radiated (fig. 1). 



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