394 



PEOF. ALLMAlSr ON THE RECENT RESEARCHES 



single more central nucleus. Besides a single (seldom more) 

 thick finger-shaped pseudopodium like those of Arcella, Schulze 

 describes numerous rounded tubercle-like processes, wbich do not 

 seem to project beyond the orifice. 



As in Arcella, an encysting process has been observed, but has 

 not been followed to its results. 



The authors believe tliat G-reefF has incorrectly assigned to the 

 genus Amphizonella the form which lie names AmpUzonella flava, 

 and wbicb they regard as identical with Pseudocllamys patella. 



The Pyxidicula operculata of Ehrenberg is another nearly 

 allied form. Claparede and Lachmann, followed by Carter, had 

 placed this rhizopod in the genus Arcella ; but Hertwig and Lesser, 

 relying on the fact of the shell being destitute of the character- 

 istic structure of that of Arcella, restore Ehrenberg's name. 



Fig. 4. 



Hyalosphenia lata. 



Viewed from the broad side, with 

 a slightly divided finger-shaped pseu- 

 dopodium. 



(After R E. Schulze.) 



Hyalosphenia lata, F. E. Schulze (fig. 4)*, is another freshwater 

 representative of the Thalamophora. It has a compressed py riform 

 test and thick finger-shaped pseudopodia. The test is a simple 

 hyaline case without any trace of structure. Included in the broad 

 aboral portion of the protoplasm is a large spherical nucleus con- 

 taining numerous nucleoli, and just in front of it lie the pulsating 

 vacuoles, which are usually two in number. There is usually only 

 a single finger-shaped pseudopodium emitted from the orifice of 

 the test. The pseudopodium, though belonging to the lobose 

 type, encloses fine granules, whose flowing movements are easily 

 seen in the axis of the pseudopodium. 



* F. E. Schulze, loc. cU. 



