AMOITG SIMPLE SAECODE OliGANlSMS. 285 



discover in it any important bearing on the life-history of the 

 animal : as a manifestation, however, of the properties of living 

 protoplasm it is full of significance. 



Fig. 9. 



Actinosphmnum Eichhornii. General view of the entire Ehizopod. «?, me- 

 dullary region (endosarc) ; r, cortical region (ectosarc) ; c c, contractile vacuoles. 

 , After Hertwig and Lesser.) 



Franz Eilhard Schulze* has made some interesting observations 

 ou the structure and development of ActinospTiceriuin Eichhornii 

 (figs. 9 and 10), which had been generally confounded with Acti- 

 nophrys sol, until Stein t insisted on the value of the differences 

 between tbem, and separated the two as distinct genera. 



The most important steps, however, in our knowledge of this 

 fine Ehizopod had already been made by KollikerJ and by Max 

 Schultze§. Kolliker had drawn attention to the peculiar vesicular 

 or " alveolar" structure of its sarcode, and to the differentiation 

 of this into two regions — a more opaque central or medullary 

 region (endosarc), and a clearer peripheral or cortical region (ec- 

 tosarc) ; while he showed that numerous nuclei were included in 



* " Ehizopodenstudien," Arch. f. mikr. Anat. vol. x. 1874. 



t Abhandl. der bohmisclien Akademie der Wissensch. 1857. 



X Zeitschr. f. wissensch. Zool, vol. i. 1849. 



§ Das Protoplasma der Rhizopoden u, der Pflanzenzellen, 186.3. 



