MONAS 757 



sometimes swim and sometimes creep, amoeba-like, by pseudopodia ; 

 but directly the diffluent sarcode of one touches that of another 

 they at once melt together, as in fig. 10, A. This leads to the rapid 

 approach of the oval bodies of the two organisms, as in fig. 11, B, 

 resulting in their fusion, as in figs. 12, 13, 14, and a still condition 

 of the sac (fig. 14) for a period of not less than six hours ; when it 

 bursts, as seen in fig. 15, pouring out an immense host of exquisitely 

 minute spores, as shown in fig. 15. These are opaque or semi-opaque, 

 but by observation upon them at a temperature of 65 to 70 Fahr., 

 they in the course of thirty minutes become transparent, elongate, 

 as in figs. 16 and 17, and, continuing to grow, assume the conditions 

 and sizes represented in figs. 1 8 and 1 9 ; and we were able to trace 

 them through all their changes of growth from the spore into the 

 adult condition, as at fig. 20, until they entered upon and passed 

 through the self-division into two described and figured in A. 



The next form, though even more simple in appearance, has a 

 much more complex morphological history. It is seen in its normal 

 form in fig. 1, C. It has but one flagellum, and, as we believe, on 

 that account has a much more restricted power of movement. It 

 is from the .^^-th to the yJ^th of an inch in long diameter. In 

 its motion at one stage of its life its oval body becomes uncertain in 

 form, as seen in 2, 3, 4, C; but when this has continued for not 

 more than a minute, the flagellum falls in upon the body, as in 4, 

 and the organism becomes perfectly still. In this condition, after a 

 space ranging from ten to twenty minutes, two white bars at right 

 angles suddenly appear, as in fig. 5 ; this is almost immediately 

 followed by another and a similar one at right angles to the first, as 

 in fig. 6. Then the circumference of the flattened sphere twists, 

 leaving the centre unaffected, so that the body assumes a turbined 

 appearance as seen in fig. 7. After this the interior substance breaks 

 up, and becomes a knot of slightly moving but compact forms, as in 

 fig. 8 ; which remains in this state for from fifteen to twenty 

 minutes, and then becomes dissociated, as in fig. 9 ; so that we have 

 here a complex form of multiple partition, giving rise to enormous 

 numbers, because, although much smaller than the form in which 

 they arose, they consume and assimilate food all over, and are 

 simply swimming in their pabulum, and so rapidly reach the 

 normal size, when they each enter upon and pass through a similar 

 process. 



But here also at certain periods there appeared forms that in- 

 augurate distinctly genetic processes. A form like fig. 10, C, appears, 

 larger than the normal form, and always mottled in the part near- 

 est the flagellum. These forms rapidly attached themselves to the 

 normal forms, as seen in fig. 11, which resulted in a blending of the 

 two as they swam together, until ' either was melted into other ; ' 

 and a still sac, shown in fig. 12, resulted. 



This remained from thirty to thirty-six hours absolutely inert ; 

 but at the expiration of that time it burst, as seen in fig. 13, D, and 

 poured out an enormously -diffusive fluid, which as it flowed into the 

 surrounding water appeared like a denser fluid, diffusing itself through 

 one of less density ; but no spores were at this stage at all apparent. It 



