10 HYALODI8CD8. 



busina. Size : in the spheroidal form, 64/j. to 160//; creep- 

 ing forms, 152// by 60^ to 340^ by 220//. 



GENUS Y. HYALODISCUS. 



SYN. : ffyalodiscus, H. and L. ; Plakopus, Schulze. 



Body naked, discoidal, consisting of a colored, granu- 

 lar endosarc, with nucleus and vacuoles, and a clear, color- 

 less ectosarc, which in the motion of the animal extends 

 in a broad zone beyond the colored mass of endosarc, and 

 projects pointed, conical processes, mostly few in number. 



H. rubicundus. SYN. : H. rubicundus, H. and L.; Plakopus 

 ruber (?) Schulze. 



Endosarc brick-red, composed of line, red granules with 

 a few larger ones of a darker shade, or else of conspicuous, 

 globular, colored corpuscules mingled with fine granules. 

 Size : 30/* to 60/*. [If Pldkopus ruber is identical with 

 this, it is much larger, being 200/* to 600^.] 



GENUS VI. DIFFLUGIA. 



SYN.: Difflugia, Leclerc ; Arcella, Ehr. ; Lecquereusia, Schlum.; 

 Homaochlamys, Heterocosmia, Exassula, Ehr. 



Shell variable in shape, usually composed of angular 

 particles of quartz-sand, mingled with diatom frustules, 

 spicules, etc., sometimes of chitinoid membrane, incorpo- 

 rated with extraneous particles, or composed in part or 

 entirely of particles of a peculiar character. Mouth in- 

 ferior, terminal, rarely sub-terminal. Sarcode almost 

 filling the shell, attached by threads of ectosarc to 

 the interior of the fundus and sides, and by a pro- 



