106 Dr. A. Gruber's Contributions to the 



XIV. — Contrilmtions to the Knowledge of the AmoebEe. 

 By Dr. August Gruber*. 



[Plate IX.] 



AuERBACiif, as is well known, starting from the assumption 

 that a membranous boundary was a necessary attribute of a 

 cell, set up a theory, quite intelligible under the circumstances 

 of the time, according to which the AmcclHe also, as unicellular 

 creatures, had a membranous envelope. This opinion was 

 refuted by subsequent naturalists ; and it was Greefi'J princi- 

 pally who gave a more correct interpretation of Auerbach's 

 observations. Witli the overthrow of this theory, however, 

 some forms of Amcehce and many of the phenomena of their 

 sarcode-body, well known to and very distinctly figured by 

 Auerbach, although not quite rightly interpreted by him, seem 

 to have been thrown into the background. 



This refers to two Amoehoe whose bodies appeared to be 

 surrounded by a double-contoured fine envelope, and which 

 were described under the names of Amoeba bilimbosa and 

 Avioeba actincphova. Tliey were afterwards again mentioned 

 by Hertwig and Lesser§, and regarded as identical with their 

 Cochliopodium^ which, however, as I shall liereafter show, 

 can hardly be the case. We must also acccj:)t similar con- 

 ditions for Greeff's || genus Amphizonella^ as distinctly appears 

 from his figure (fig. 18) of the colourless species. 



The existence of a fine layer of clear protoplasm round the 

 Amoeha-hodj ^ which must be penetrated by the pseudopodia, 

 seems to me to be by no means an insignificant phenomenon 5 

 and I hope to excite some interest by citing another form of 

 Amoeba of the same kind and by a fresh investigation of 

 Auerbach's Amoeba actinoj^hora. 



1. Amosba tentaculata, sp. n. 



I found the Ama'ba\f\\\c\\ forms the subject of the following 

 consideration in the small sea-water aquarium of the Zoological 

 Institute here [Freiburg im Br.]. The water and the vege- 

 table and animal organisms contained in it are chiefly derived 



* Translated from the ' Zeitsclirift fiir wissenschaftliche Zoologie,' 

 Band xxxvi. pp. 459-470. 



t Auerbach, " Ueber Einzelligkeit der Amciben," Zeitschr. f. wiss. Zool. 

 Bd. vii. 



X Greeff, ' Ueber einige in der Erde lebenden Amoben und andere 

 Rhizopoden,' 



§ Ilertwig und Lesser, '' Ueber Rhizopoden und ihren verwandte 

 Organismen," Arch. f. milcr. Anat. Bd, x. Supp. 



II Ai'ch. f. mikr. Anat. Bd. ii. 



