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Iho struclurn of which varies lo th(^ samo extent as in indi- 

 vidiuils C. SoinotiiiK^s I ohsorved a Imi;^- ehroniatiii lliread 

 coiled arotiml the karyosoiiie. It is possihh^ (hat such luicloi 

 are }>reparii)ii" Tor dixision. 



it is very dilTicidt to trace tlie orij^iii of individuals /-;. 

 Altliou^h, Jud^-iUK fi'oiii some jircparatioiis, (hey derive from 

 iiDiiHicleate individuals by means of liivision of the nucleus 

 accompanied hy (he formation of a spindle outside the nuc- 

 leus similar (o that in individuals I). 



There remain to l>e said a few words about cerlain for- 

 mations whiclt are })roduced by a chan<j:e in (he (ype E. 

 Amongst the coidents of (he intestine of llodoteniies there 

 are sometimes to be found small (30—35 microns in diameter) 

 balls (tab. Ill, fig. 38), consisting of homogeneous finely 

 granulated plasm Avithoiit any inclusions, exce])t a large nucleus 

 situated near the surface of the boll. The nucleus is somewhat 

 elongated and built according to the nucleus type of the E 

 individuals: to it is closely adjacent a small undulating mem- 

 brane projecting above the surface of the body. At first the 

 origin of such forms of Myxomonas was inconceivable for 

 me, until I met with the stages drawn in fig. 41, tab. IV. 

 Here we see a Myxomonas of type E, the plasm of which 

 becomes more fluid than is usiud; portions of the protoplasm 

 separate from the body and, rounding out, they form balls. 

 Some of these balls are small and consist of plasm alone, 

 while others are larger and contain a nucleus with the cor- 

 responding membrane. Such products of breaking up of the 

 type i^ individuals correspond to the fornuitions just describ(d 

 by me (let us name them type F). 



The genetic relations between the different types of Myxomonas. 

 As may be seen easily from my description, I was far from 

 having at my disposal all the stages of the cycle of develop- 

 ment of Myxomonas; for instance, the sexual stages of re])ro- 

 duction remain unknown. As concerns the stages described 

 by me, the relations existing between them seem (o me to 

 bear the following aspect. The fiuidanu'iital form is presented 

 by the uninucleate individuals of type C with a small undu- 

 laiing membrane. These individuals may encyst, after rounding 

 out and becoming richer in chromidia. (hi the other haii'!, 

 after feeding (see the rare cases, when food was found in 

 individuals C) they may give origin to biiuicleate amoebae of 



