Boyal Microscopical Society. 267 



from tlie prominence of otlier phenomena, we did not with any 

 continued intensity follow it up. This past summer we made it a 

 specific object, and by dint of close application found that, in 

 comparison with other phenomena, very occasionally two of the 

 monads, at times in no way distinguishable from each other, met 

 and touched each other at their anterior ends, swimming freely 

 together, as seen in Fig. 21. The normal flagella rapidly dis- 

 appeared, and the bodies melted into each other ; another stalked 

 double flagellum appearing at one end in a manner never in any 

 way understood by us. The nuclear bodies a, h, Fig. 21, blended 

 also into one ; the whole thing in this stage being shown at Fig. 22, 

 where also an intensely granular state peculiar to this condition is 

 shown. This body preserved its freedom of motion for a long time 

 — occasionally for ten or twelve hours — but during this time it lost 

 slowly the line of juncture, and became oblong and then rounded ; 

 after which its motion was more sluggish, and it eventually 

 became quite still. Fig. 23 represents it in this condition. It 

 remained in this state sometimes as long as twenty-four hours ; but 

 generally, from four to six hours was the time occupied before any 

 changed ensued. The uncertainty, however, made constant watch- 

 ing absolutely necessary. The whole sac showed as the first 

 symptom of change a slight vibration or wave-like motion, and 

 then, with no further premonition, its edges broke up and a cloudy 

 mass poured out, in which with competent powers it was compara- 

 tively easy to detect myriads of minute points. Fig. 2-1 depicts 

 this ; and by following up rigorously these emitted poiats, we found 

 that after a short period of inactivity they became motile, and 

 rapidly grew, acquiring flagella, and becoming perfect monads of the 

 parent type. Not only so, but these very forms were persistently 

 followed, and were seen to increase by multiple fission, and to 

 deposit granules as before described. At times the globular con- 

 dition was not taken, but the emission took place in the condition 

 shown at Fig. 25. It will be seen that this, and another form 

 which we hope to describe in a subsequent number, gave us more 

 trouble and perplexity than any we had worked at. But after 

 working the whole life cycle out it now appears to us that this 

 monad primarily multiplies sexually by the congress of the genetic 

 elements. This, however, is comparatively a very rare occurrence, 

 and serves for many (probably) hundreds of generations. But a 

 kind of parthenogenesis, or internal budding, follows — resulting in 

 the emission of the sarcodic granules which contain minute monad- 

 germs — this being by far the more frequent and rapid m.ode of 

 increase ; while at the same time multiple fission is taking place in 

 all directions. 



Thus we have the minute germ sexually produced; the bud 

 produced in large quantities within the unfertilized form, both 



