108 BEITISH FRESHWATER RHIZOPODA. 



reddish body is seen to form only the central region, 

 which is surrounded by a colourless and hyaline border. 

 Then the appearance of the organism is that of a 

 colourless disc, with a granular, coloured mass occupy- 

 ing ordinarily a central position, but sometimes 

 posterior. The margin is homogeneous and structure- 

 less, and is seen with difficulty, while the central 

 coloured region is more or less sharply defined. The 

 authors observed in the endoplasm a variable number 

 of greenish-brown bodies which they regarded as more 

 or less accumulated food-substances, of vegetable origin, 

 becoming more reddish with the progress of digestion, 

 and mingled with them were numerous vacuoles, which 

 at times were difficult to be made out owing to the 

 opacity of the body-substance. 



This organism sometimes exhibits a degree of 

 mobility, occasioning variations of form and appear- 

 ance, which renders it difficult of identification. Its 

 progress being intercepted by any object, the disc-like 

 body will double back upon itself, and the animal will 

 set off in some other direction. This seems to be the 

 habit represented by Schulze in his figures and descrip- 

 tion of the organism which he named Plalcopus ruber, 

 but which there is little reason to doubt was the Hyalo- 

 discus rubicundus of Hertwig and Lesser. 



According to Schulze one or more nuclei are present, 

 not readily observable in the ordinary state, but under 

 reagents becoming evident. A comparatively large 

 nucleolus is. surrounded by a clear round border, with 

 its outer limits only seldom sharply marked. It is 

 remarked also (referring to Plakopus ruber} that a 

 variable number of different-sized pellucid vacuoles is 

 scattered through the body-mass. This is character- 

 istic of our Cheshire examples. The outer hyaline 

 stratum is, under a high magnification, faintly granu- 

 lated. 



The mode of reproduction of this organism has 

 not been sufficiently studied. In all probability it is 

 analogous to that of Vampyrella. 



