556 JOHNSON. 



EXPLANATION OF PLATE XXIIL 



Fig. I. Stentor ignetis var. nigricans, var. nov. From Williamstown, Mass. 

 Ventral aspect of a living, semi-contracted specimen, under slight cover-glass 

 pressure. X ca. 250. 



Fig. 2. Stentor pyriformis, sp. nov. Ventral aspect of a living, fully-extended 

 specimen (outlined vv'ith camera). X 230. 



Fig. 3. S. pyriformis. Hardened and stained preparation to show mega- 

 nuclei. X 1 10. 



Fig. 4. ^S". roeselii. Living, extended specimen, containing numerous minute 

 algae taken in as food. Dorsal aspect. Zeiss, obj. A. oc. 4. 



Fig. 5. Transverse optical section of ectoplasm and pellicula of S. cartdeus. 

 The pellicula is adherent only over the myonemes. 1% osmic acid preparation. 

 Zeiss, 4 mm. apoc. obj., oc. 4 = X 433. 



Fig. 6. Part of adoral zone of S. ccE7'iilais. Living specimen under strong 

 pressure. Zeiss, 4 mm., apoc. obj., oc. 12 = ca. 650. 



Fig. 7. Two adjacent rows of cilia and myonemes, frontal field of S. cceruleus. 



Osmic acid preparation. Zeiss, -7-7^ (cam.) = X 1950. 



Fig. 8. Posterior face of transverse section of S. ccErulens, taken at time of 



greatest concentration of meganucleus in fission. Zeiss, -—^ — = x 230. 



Fig. 9. ^\.xv^Q.% oi S. pyriformis. I % osmic preparation. Zeiss, — - — ■= X 433- 

 Fig. id. Myonemes of ramifying zone, S. cceruleus. In relaxed condition. 



Living specimen under strong pressure. Zeiss, . 



Fig. II. Myonemes of S. cczruleus. From specimen fixed with picro-acetic, 

 stained with borax-carmine. Zeiss, Homog. immers., 2 mm., oc. 2 = X 428. 

 Fig. 12. Posterior extremity of S. cceruleus. 1% osmic preparation, flattened 



by cover-glass. — - — = x 41 1- 

 •' ° 4 mm. ^-^-^ 



Fig. 13. Longitudinal optical section of new adoral zone of S. cceruleus. Cor- 

 rosive sublimate preparation, 5 = X 380. 



Fig. 14. Foot of S. ccertcletts, attached to surface film of water. Zeiss, -7^ — . 



16 mm. 



Fig. 1 5. Foot of S. roeselii, attached in slime. Zeiss, 5- . 

 Fig. 16. Foot of S. polymorphus, attached to glass. Zeiss, 5- . 

 Figs. 17, 18. Abnormal forms of meganucleus, S. cceruleus. (17, 



16 mm. 



X 112; 18, f = X 230.) 



Fig. 19. Two nodes of meganucleus, S. cceruleus, with adherent micronuclei 

 (men.). The nodes contain vacuolar spaces. Aceto-methyl-green preparation, in 

 H^O. ^^= X 433- 



4 mm. ^ ^•'•^ 



Fig. 20. Node of meganucleus, S. cceruleus, with several vacuolar spaces of 

 different size, containing each a highly-refractive body. Aceto-methyl-green, 

 glycerin. Zeiss, g- = X 550. 



Fig. 21. Meganucleus of ^. igneus, elongated for division. Median optical 

 section, showing chromatic network. Aceto-methyl-green, H2 O. Zeiss, ^ = 

 X630. 



Figs. 22-24. Nuclear multiplication in S. igneus. Zeiss, | = X 230. 



Fig. 25. Meganucleus, S. ignetis, with adherent micronuclei. Corrosive subli- 

 mate, borax-carmine, benzole-balsam. Zeiss, 2 mm. homog. immers., comp. 

 oc. 4 = X 857. 



