RECENT MEMOIRS ON FRESHWATER RHIZOPODA. 307 



chyma of the ectosarc, the whole body becoming contracted 

 into an irregularly rounded or ovate figure, the endosarc 

 gradually losing its alveolar structure, and becoming con- 

 densed into a compact darker granular mass, and acquiring 

 an almost smooth sharp limitation from the still alveolar 

 clear ectosarc ; now began the excretion of a rather thick, 

 gelatinous envelope, showing here and there some concen- 

 trically stratified layers of granules, a few such here and 

 there on the periphery ; at other places appearing destitute 

 of them, but not very sharply bounded. 



Under favorable circumstances a number of clear spots were 

 perceptible in the opaque endosarc, indications of so many 

 nuclei. 



In about half a day the first sub-division of the whole 

 mass, along with the gelatinous envelope set in, and con- 

 tinued by binary sub-division, so that in from one to two 

 days, say 10 to 30 subsequently approximately globular 

 bodies resulted, though at first (or even continouslyj somewhat 

 flattened by mutual contact, each enveloped in, as it were, 

 its share of the simultaneously sub-divided alveolar cortex, 

 now, however, having lost its alveolar structure. Imbedded 

 in the centre of each there now appeared a single nucleus, 

 which, when extruded by pressure, along with the granular 

 body-substance, showed its large, dark nucleolus. 



Thus Schulze's observation does not at this point concur 

 with Schneider^s, who found the sub-divided portions multi- 

 nucleated, not single nucleated, that is to say simple cells, 

 and who avers these latter to be enclosed in twos within a 

 solid oval cyst. Still Schulze confirms Schneider so far that 

 the clear cortex becomes ultimately silicified, but could not 

 agree with him that this envelope was made up of siliceous 

 pieces with intervening spaces, but it rather appeared as a 

 membrane with either vacuities therein or external depres- 

 sions. The inner mass sometimes showed slight temporary 

 retrocessions from the wall,'soon disappearing probably to re- 

 appear at a new place. 



The author's train of direct observation became here broken, 

 yet from renewed examination of other specimens he records 

 further as regards the young animal, after emergence from 

 the siliceous capsule, that it consists of a very thick, clear, 

 alveolar ectosarc, not as yet very sharply differentiated from 

 the sparingly granular endosarc, which latter encloses but a 

 single clear nucleus of quite similar appearance to the mul- 

 tiple ones of the fully-grown examples ; the pseudopodia are 

 of greater tenuity than when fully-grown, the axis scarcely 

 perceptible owing to its delicacy. During the following 



