ON BIOLOGICAL ANALOGIES. 265 



experiences of the changes he saw taking place from the simple 

 Protococcal cell to the Amoeboid form. The details can be referred 

 to of this completion of the cycle of " a flagelliferous phase, an 

 amreboid condition, and an encysted sporiferous state," and yet we 

 are not aware that Chlamydococcus has been referred to the " Pro- 

 tozoic division of the animal series." 



We all know Volvox globator, but we have not all of us seen it 

 pass through the Amoeboid stage, and yet Dr. Braxton Hicks 

 (" Trans. Micr. Soc," 1860, p. 99) describes this stage, when the 

 cells " have a curious power of changing shape, like an infusorial 

 Proteus, protruding the wall, first at one side and then at another, 

 into which protusions the contents pass." A year or two subse- 

 quently these observations were confirmed by the same author in a 

 most interesting paper (" Quart. Journ. Micr. Sci.," 1862, p. 96), 

 with additional details. " It has the power of protruding and re- 

 tracting, in various parts, portions of the primordial utricle, exactly 

 and to the full extent of a true Amoeba. By this power they glide 

 along the inner surface of the sphere among the unchanged zoo- 

 spores, and when they come in contact with one they bend them- 

 selves round it in the manner of the Amcebce." 



Another observer, Mr. Archer of Dublin, has traced the develop- 

 ment of Amoeboid forms from another undoubted unicellular Alga 

 (Stephanosphcera pluvialis). " It will readily be believed that my 

 astonishment was beyond measure great," he writes, " upon, beyond 

 all question, identifying these vigorously active Amoeba-like bodies 

 with the, just previously, quiescent primordial cells of the Stephano- 

 sphara — nay more, in watching the transformation of the latter them- 

 selves into the repent amoeboid bodies, putting a parasitic develop- 

 ment wholly out of the question ; it will readily be believed, I say 

 that my astonishment was beyond measure great, in actually 

 witnessing with my own eyes this, at first sight, sufficiently 

 startling phenomenon.*' * 



But observations of this kind have not been confined to Alga?. 

 Hartig, in 1856, watched the development of Amseboid forms from 

 Chara and Polytrichum (" Quart. Journ. Micr. Sci.," 1856, p. 51), 

 and in the Amcebce of the Characece he observed a remarkable 

 circulation similar to that which occurs in the cells of Chara. We 

 can hardly be surprised that above a quarter of a century ago he 



* " Quart. Journ. Micr. Sci.," 18G5, p. 125. 



