T.-' face p. 176] 



DESCRIPTION OF PLATES. 



Plate I. 

 [. — .-I Heteroiiiita roitrata (Kent), 

 t _B. Monas DaUhigen (Kent). 



! — C. D. H. rostidta undergoing fission. This was seen in earlier studies to 

 begin in the body, and apparently afterwards (as in c, d) to extend to the 

 nucleus. 

 J —Almost complete division of the body and the nucleus of the same ; but a 

 1 exists between the two parts of the nucleus. 



ind the division of the body and the 



-Total severance of the nu 

 flagella is almost complete 



-A H rostiiita produced by fi 



-The final product of a long : 

 preceding sexual fusion, 



8 -The process of fi: 



-The initiation of fu 



I of fissipartitions undergoing the change 



this special form, 

 m ordinary form v 



-Early result of fusion of tw 



exhibits a radial conditio 



-A sac resulting trom the cc 



-The ripe sac bursting and > 



■> of these forms ; the nucleus has blended, and 



Figs, 

 Fig, I 



nplete genetic fusion of the two individuals, 

 mitting minute semi-opaque spores 



1 — A study with great magnification of the nucleus separately This repre- 

 sents the nucleus before any evidence of change is discoverable 



I— The first evidence — seen only in the nucleus — of approaching fission in the 

 organism ; beaded threads appear throughout the plasm ; and a line 

 shows itself incident with the long diameter of the organism, 



j — The fission begins in the body at a. but has been preceded by a con- 

 densation of the beaded structure to the right and left of the division- 

 line 



6, 17, 18 — The nucleus seen in process of fisi 

 Fig 3, pi i ) and immediately after divis 



3. — Nucleus after division in the exceptional form show 



3. — Condition of the nuclei in the fused forms 



[. — g, h. i. Growing spores, 



i.—j. The spore grown to the size of a nucleus, a pause takes place in actual 

 enlargement by growth, and internal development of the beaded structure 



J —After the internal development of the nucleus the body begins to great 

 apparently from the nucleus, and the flagella. /. m, are pushed out ; after 

 this, growth to the normal size is rapid. 



almost divided (as seen i 

 Fig S. h. pi, i. 



Natural Science, Vol. II. 



