No. 3.] MORPHOLOGY OF THE STENTORS. 529 



plasm, and, caught in the endoplasmic cyclosis, are carried to 

 all parts of the animal. It is a striking fact that the proto- 

 plasmic circulatory movements are far more active at time of 

 conjugation than at any other period in the life of Stentor 

 that I have observed. The arrangement of cytoplasmic 

 threads about the separated nodes of the meganucleus (Fig. 

 51) reminds one strongly of the streaming reticulum in 

 Noctiluca or in the stamen-hairs of Tradescantia. 



Micronuclei of different sizes and stages of development can 

 be seen in the living gamete, and the movement of these is 

 quite as active as that of the nodes. They have a glistening, 

 refractive appearance. I was never able to see a micronuclear 

 spindle in the living animal, the most of the micronuclei 

 observed being probably already developing to become mega- 

 nuclei {Fig. 50, nigu.^ ?). 



By reason of the difficulty in obtaining material, and not 

 less, perhaps, on account of the obscuration of the micronuclei 

 by the comparatively great mass of cytoplasm, no adequate 

 account of the complex details of conjugation in any species of 

 Stentor has been given. The latter difficulty I have obviated 

 by sectioning the gametes, which can be readily oriented. I 

 have endeavored to secure material by the method used by 

 Maupas ('89, p. 168), but without the least success. ^ 



While it wovdd be impossible to interpret the results I have 

 obtained from the small amount of material at my command, if 

 we had a less complete knowledge of conjugation in other 

 forms, I believe it may be done in the light of the beautiful 

 researches of Maupas ('89) and of R. Hertwig ('89) in this field. 



Nearly all of my preparations show that the gametes were in 

 the later stages of conjugation (Stage H of Maupas), and 

 consequently I have not seen the exchange of micronuclear 

 spindles. In only one preparation have I found spindles, two 

 of different shape (from the same gamete) being represented in 

 Figs. 53, 54. They are both in the "monaster" or "mother- 

 star" stage, and have longitudinal, linear chromosomes which 



1 I have also tried Maupas' method with Paramecium candahim, which multiplied 

 enormously in hay infusion, and was afterwards subjected to long periods of 

 fasting, but obtained no "epidemics" of conjugation. 



