JENNINGS— HEREDITY IN PROTOZOA. 



443 



Seventh Stage: Fission. 



Some of the data bearing on the dimensions during fission have 

 been incidentally taken up in the account of the young in the earliest 

 stages, before the two halves have separated, 



(m) Beginning Fission. Descendants of D (caudatiim Form). 

 — Four lots of dividing specimens descended from the individual D 

 were studied. These lots were taken at different times; the first 

 included 313 dividing specimens (Tables XL and XII., and rows 

 25-29, Table X.) ; the second 62 (Tables XLIL, XLIII. (appendix) 

 and rows 30-32, Table X.) ; the third yy (Table XLIV., and rows 

 23-24, Table X.) ; the fourth 37. The dimensions of random sam- 

 ples of the same lots are given in Table X. 



The large lot containing 313 dividing specimens may be described 

 as typical ; the others show the same relations, except as hereafter 

 noted. 



Table XIV. 

 Correlation Table for Random Sample of Specimens not Dividing, of Lot 



I (from which came the dividing specimens of Table XIII.). (See 

 Table X., row 27.) 

 Length in [Microns. 



'^flOlO^vO^ t-»t^COC«00 ONONO O O >-i 1-1 C^ C< tN rO rO -^ 

 MMi-(wl-li-i>-.Mi-iP-ci-(>Hi-ip<fN|C>)MMP<MC<OIMM 



4 

 12 



44 

 38 

 47 

 33 

 14 

 6 



2 I 2 o I 3 3 6 II 16 22 19 28 17 18 II 15 13 7 3 o 2 200 



Length — Mean, 199.960 ± .740/^ Breadth — Mean, 50.220 it .308/* 



St. Dev., 15.528 ± .524M St. Dev., 6.468 ± .2i8At 



Coef. Van, 7.765 ± .263 Coef. Van, 12.877 — -441 



Mean Index, 25.114 per cent.; Coef. Cor., .6064 ± .0302. 



In the dividing specimens the length of the body increases as the 

 depth of the constriction between the two halves becomes greater; 

 this is well shown in Fig. 2, page 416. In order to include only the 

 earliest stages of fission we shall, of course, have to take the speci- 



