208 SUMMARY OF CURRENT RESEARCHES RELATING TO 



addition, the two flagella never completely disappear, however much 

 they may be hidden from view ; nor is the body perfectly round. 

 The study of its developmental history was, unfortunately, only 

 incompletely carried out. 



The author concludes by discussing the doctrine of Bergh that 

 the Cilio-flagellata are the lowest forms ; to this he cannot give his 

 adhesion, believing rather that the Ehizopoda stand nearest to formless 

 Plasmodia. 



Contributions to the Knowledge of the Amoebae.* — Dr. A. Gruber 

 points out that Auerbach,f starting from the assumption that a mem- 

 branous boundary was a necessary attribute of a cell, set up a theory, 

 according to which the Amoebfe also, as unicellular creatures, had a 

 membranous envelope. This opinion was refuted by subsequent 

 naturalists, principally Greelf,J but with its overthrow some forms of 

 Amcebce and many of the phenomena of their sarcode body, well known 

 to Auerbach, although not quite rightly interpreted by him, seem to 

 have been lost sight of. 



The existence of a fine layer of clear protoplasm round the 

 Amceba body, which must be penetrated by the pseudopodia, is by 

 no means an insignificant phenomenon, and the author therefore 

 considers it useful to describe another Amceba of the same kind (A. 

 tentaculata), and to reinvestigate Auerbach's A. actinophora. 



1. Amceba tentaculata sp. n. was found in a small sea-water 

 aquarium, the water and organisms being chiefly derived from the 

 Frankfurt aquarium, but mixed with some from the Baltic and 

 Mediterranean. 



It forms a little mass of very variable size, • 03 mm. to • 12 mm. 

 In consequence of its greater refractive power, the body stands out 

 luminously from the water, a property which in the protoplasm of all 

 Ehizopoda goes hand-in-hand with greater viscosity. We find the 

 rule confirmed here, for the protoplasm of A. tentaculata is, in fact, 

 an extremely tenacious mass, in comparison with that of allied 

 creatures. 



Under a power of 80 we can see no movement or change of form, 

 and it is only wdth high and very high powers that we can recognize 

 an Amceba in continual although sluggish change. 



Examined in the resting state, it has essentially the same form as 

 A. verrucosa ; i.e. the whole body is shrunk together, and covered 

 with elevated knobs and deep folds which slowly change their form 

 and position. 



In the interior the vital activity of the protoplasm is manifested 

 by a streaming and trembling movement of the fine dark granules 

 with which the sarcode is abundantly furnished. 



But while in A. verrucosa we miss true pseudopodia, both in the 

 resting state and during flow, we are surprised here by seeing fine 



* Zfitschr. f. wiss. Zool., xxxvi. (1881) pp. 459-70 (1 pi.). See Ann. and 

 Mag. Nat. Hist., ix. (1882) pp. 106-16 (1 pi., the use of which has been 

 obligingly allowed us by the publishers). 



t " Ueber Einzelligkeit der Amoben," Zeitschr. f. wiss. Zool., Bd. vii. 



j Greeif, ' Ueber einige in der Erde Icbenden Amoben und andere Rhizopoden.' 



