202 Egbert Thompson Young, 



plate. In Figs. 18, 31, 33, 34, 40, is seen verj' strong presumptive 

 evidence in support of this view. Let the reader consider for a 

 moment Fig. 32. One finds here a parenchyma cell containing five 

 chromatin granules, from the largest of which there extends out 

 thru the nuclear membrane a deeply stained process which I inter- 

 pret as the rudiment of the ciliate process of a flame cell. Again 

 in Fig. 31, the apparent direct continuity between ciliate process 

 and chromatin granule in the nucleus, is certainly very suggestive. 



In Fig. 30 may be seen the ciliate process well formed and in 

 intimate contact if not organic union with the nucleus. Lying just 

 within the nucleus and close against the base of the ciliate process 

 are two small chromatin granules, while near them is a third similar 

 in shape and size. It may very easily be conceived that the process 

 has had a common origin with these granules, which will ultimatelj^ 

 increase in size and, fusing, form the basal plate. 



In this connection the description and drawing of a developing 

 flame cell in Amphilina given by Pintner (1903, p. 50) is of interest. 

 He says, referring to his fig. 35a, tab. 4, "An der Delle zeigte der 

 Kern eine dichte schwarz gefärbte Chromatinlage und über derselben 

 einen Bogen schwarzer Kügelchen". The possibility of the origin 

 of basal plate and ciliate process from this "Chromatinlage" and 

 "Bogen schwarzer Kügelchen" is here strongly suggested. But do 

 not such cells as are represented in Figs. 21 and 37 militate against 

 such an hypothesis? Not at all. For the structure presented by 

 such cells may readily be explained in either one of two ways. 

 Firstly, the basal plate and ciliate process may be supposed to have 

 originated in the nucleus and migrated out from it. Or again they 

 may have developed in the cytoplasm simultaneously with, or even 

 prior to, the development of the nucleus. 



In Fig. 33 I find evidence in favor of the second view stated 

 above, for here are seen what I interpret as two successively 

 younger stages in chromatin development. First, the basal plate and 

 ciliate process well developed lying just on the edge of the large 

 formative mass of cytoplasm^); and second, two developing nuclei 

 lying in this mass, the first, x, a crescentic-shaped nucleus with a 

 fairly distinct membrane and containing a few granules of chromatin 

 barely discernible with a magnification of 2850 diameters, and the 



1) See under Cytogenesis a discussion of these "formative masses of 

 cytoplasm". 



