262 Mt. H.J. Carter on Difflugia pyriformrs; 



have become altogether reptant and amoebous. Their sizes 

 average between - ^^^ ^ th and ^-^Votli part of an inch in diameter, 

 the former being that of the globular, and the latter that of the 

 plane or amoebous forms. This has been confirmed by a repeti- 

 tion of this experiment. 



Now, as the granuliferous cells on the watch-glass are so 

 much like those in the interior of the colourless specimens of 

 Difflugia pyriformis (which granuliferous cells have heretofore 

 been inferred to have come from the spherules of the nucleus in 

 the coloured or green state of the animal), and there is no other 

 source in the watch-glass, apparently, from which they could 

 have been derived, while the four Diffiugice are still alive (for 

 this is a necessary adjunct, since we are now among a class of 

 beings where the death of one frequently affords nutriment for 

 the almost instantaneous evolution of another species), and a 

 gelatinous mass is projecting from their apertures respectively, 

 which may also be inferred to be the protoplasm charged with 

 the granuliferous cells, there can be no reasonable doubt that 

 the granuliferous cells of the watch-glass came from these Dif- 

 flugicE. And when we find that a cilium is added to them, 

 that they are polymorphic, and that some have lost this cilium 

 and have assumed an amoebous state, which strictly accords 

 with what has been seen in the generative development of the 

 rhizopodous cell of Nitella, there can be just as little doubt that 

 these AmoehcB are the young brood of Difflugia pyriformis. Thus 

 the cycle of generative development in Difflugia 2)yriformis, by 

 '' granulation of the nucleus,^'' is so far completed. It is pro- 

 bably the same in A^noeba princeps. 



The next step will be to follow the development of the young 

 Amoebce into the adult testaceous Difflugia. But this will be 

 much more difficult, since it may not take place for many mouths, 

 during which time these little Amcehce may become j)'>'o tempore 

 inhabitants, and probably subsequent destroyers, of vegetable 

 cells into which they have penetrated for nutriment. Myriads, 

 of course, as in evei'y other case, are themselves destroyed by 

 the contingencies which intervene between infancy and adult age. 



While studying Difflugia pyriformis, it has been my good 

 fortune to meet with two specimens of another Rhizopod con- 

 taining chlorophyll-cells and refractive amylaceous granules as 

 normal parts of the animal ; but this novelty, if such it may 

 now be termed, does not rest here ; for this Rhizopod, which 

 I at first thought to be a loricated Actinophrys, proves, on fur- 

 ther examination, to be so nearly allied to Acanthometra among 

 the Echinocystidia, that I cannot help viewing it as a freshwater 

 species of this order, and shall for the present describe it as 



