68 GARY N. CAI.KIN>. 



DESCRIPTION OF PLATES. 



Unless otherwise stated, all figurr- an- made from camera diawings or -keu ln-- 

 from the living cells. The black line? indicate the planes of cutting. All tigmes 

 are of Parameeium caiidatuin. 



PLATE I. 



FIG. i. a, vegetative cell cut in zone i ; b, the fragment at the end of four hours. 

 It tiled within 24 hours. Kxp< i iinent II, Table I. 



!!<,. 2. a, a similar cell cut as above; b, fragment 72 hours afterwards showing 

 neither regeneration nor growth. Experiment 4, Table I. 



Fi<;. 3. a, conjugating ]'in-<in-i iitm cut in zone 2; b, fragment 24 hours after 

 the operation; c, rlie other, normal, cxconjugant; d, the fragment fixed and stained 

 after 96 hours, showing normal vegetative nuclei indicating that conjugation had 

 just begun when cut. Experiment 2, Table II. 



FIG. 4. a, vegetative cell cut in zone 2; b, the fragment 6 hours after cutting; 

 c. the fragment dividing 24 hours after cutting and killed during division to show 

 the nuclear apparatus. Experiment 7, Table II. 



FH.. 5. a, vegetative cell cut in zone 2; b, fragment dividing, 16 hours later; 

 c, anterior, and d, posterior, cells killed 24 hours after division for the nuclear 

 structures. The disintegrated fragments of macronuclei indicate recent conju- 

 gation. Experiment 9, Table II. 



FIG. 6. a, vegetative cell cut in zone 2; b, fragment 24 hours after cutting, with 

 tentacle-like process; c, fragment dividing in the original center of the cell 48 hours 

 after cutting; d, e, resulting daughter cells 6 hours after division. Both of these 

 cells died on the following day. Experiment 21, Table II. 



FIG. 7. a, vegetative cell cut in zone 2; b, fragment 72 hours after cutting; 

 c, fragment in division on the fourth day; d, e, daughter cells resulting from this 

 division;/, cell d on the sixth day, much grown; g, h, daughter cells of /on the ninth 

 day; /, j, daughter-cells of /; on the twelfth day; k, I, daughter cells of g on tin- 

 twelfth day; m, n, figures of i and k on the seventeeth day when they died; o, figure 

 of j on the eighteenth day after the operation when it, too, died. Experiment 54. 

 Table II. 



FIG. 8. a, vegetative cell cut in zone 2 near the plane of division; b, division 

 of the fragment 24 hours after cutting; c, d, resulting cells, the former minute, the 

 latter normal. Both died on the second day. Experiment 29, Table II. 



FIG. 9. a, vegetative cell cut in zone 3; b, fragment 12 hours after cutting; 

 c, same dividing 24 hours after cutting; d, e, daughter cells resulting from division 

 of b;f, division of truncated cell e on the fourth day; g, figure of truncated posterior 

 half of /on the eighth day; h. i, daughter cells of the normal half of/, on the tenth 

 day, j. figure of g on the tenth day. Experiment 19, Table III. 



FIG. 10. a, dividing cell cut in zone 3; b, division figure aiiei removal of tin 

 anterior end; c, small anterior cell alter division; </, normal posterior cell alter 

 division of b; e, figure of c 24 hours latei ; f, li-me oi </, J4 hours alter di\ ision of b. 

 Experiment n, Table II. 



Fit;. 11. a, dividing cell cut in zone 4; b, posterior liagment with mass of 

 crystals in the anterior end. This died on tin ii.llnwing day. Experiment 5, 

 Table IV. 



FIG. 12. a, ex-conjugant cut in zone 3; b and c, tin anterior fragment 4S and 

 96 hours after cutting. 



