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THE AMERICAN MONTHLY 



fine rays were visible about these 

 bodies, and they assumed the form 

 of a young Actinophrys. In this 

 earlier stage there was much resem- 

 blance to small Amoeba radiata, but 

 the development of the different 

 specimens left no reasonable doubt 

 that the Actinophrys has this appear- 

 ance in its earlier stages of growth, 

 and this is confirmed by subsequent 

 observations to be noted. 



A fact which appears to me impor- 

 tant is this : that I was not able to 

 trace fission in any specimen be- 

 ginning with the single spherical in- 

 dividual. In all the dumb-bell forms, 

 whether the neck were thicker or 

 smaller, the lobes had each its own 

 center from which its rays projected, 

 making two or more radial systems ; 

 and, though I watched with patience 

 for an instance of such beginning of 

 fission in a single specimen, I have 

 never found it. On the other hand 

 the cases of conjugation were ex- 

 tremely numerous, and were traced 

 in very many instances through the 

 whole process to ultimate fission 

 again. In the cases in which this 

 subsequent separation took place, the 

 several individuals did not lose their 

 identity in the union, but the case re- 

 mained one of conjunction as distin- 

 guished from complete coalescence. 

 The ray-systems of the individuals 

 and the central circle of each, re- 

 mained throughout. All the cases 

 of apparent fission which I observed 

 were, therefore, precisely such as oc- 

 curred when conjugation had taken 

 place before ; and though dumb-bell 

 forms were constantly met with, 

 which I had not traced through pre- 

 vious stages, they all, for aught that I 

 had seen, might most naturally be re- 

 garded as cases of conjugation. 



In some instances there was evi- 

 dence tending to show that complete 

 coalescing might follow conjugation, 

 the body then going into the opaline 

 state which I am about to describe, 

 but I prefer to treat this as doubtful 

 till confirmed by more thoroughly 

 traced examples. 



The Opaline Condition. — The 

 Actinophrys was frequently met with 

 in a condition which I have referred 

 to as opaline, and it frequently was 

 seen to pass into this condition after 

 conjugation and subsequent separa- 

 tion. The whole body assumed a 

 bluish, milky hue, and appeared di- 

 vided into spherical cells of varying 

 sizes, the number of these gradually 

 diminishing and the size increasing. 

 The rays became less numerous, 

 smaller, and disappeared. In some 

 cases before doing so they lost their 

 radial direction and fell across each 

 other like sponge-spiculae (Fig. 44). 

 If we suppose a partly solidified en- 

 do-skeleton to be absorbed before the 

 solid parts of the rays, the successive 

 phenomena would be intelligible, and 

 this occurrence is part of the evidence 

 bearing on that question of structure. 

 The large opaline cells were much 

 more transparent than the animalcule 

 had appeared before, so that it was 

 now practicable to focus up and 

 down through the body, passing 

 from the upper to the lower cells in 

 turn. In the usual condition of the 

 Actinophrys, everybody knows that 

 this is impossible, though the animal- 

 cule is colorless. In these opaline 

 cells are seen very small, highly re- 

 fractive granules, very nearly opaque 

 but highly colored, red and green, 

 which kept up the active movement 

 before mentioned as resembling the 

 Brownian movement. When the rays 

 had disappeared, and sometimes be- 

 fore they were quite gone, the body 

 seemed every way more plastic than 

 in its usual condition, totally losing 

 the firmness or rigidity which then 

 marks it. Its surface sprouts into 

 gemmae more or less persistent, some 

 of these taking the form of a central 

 body with several radial arms, others 

 being more like pseudopods of amoe- 

 boid character, club-shaped and of 

 varying rounded outline (Fig. 45). In 

 the cases I observed, although some 

 of these seemed at times as if almost 

 severed from the parent body, I did 

 not see that separation occur, and 



