WENRICH: spermatogenesis of PHRYNOTETTIX MAGNUS. 91 



especially true of the distal pole, as shown in figure 18. It would seem, 

 therefore, that the vesicular membranes first became formed, then 

 largely disappeared, and later reappeared in part. I am inclined to 

 believe that they actually persist to a greater extent than is apparent. 

 There cannot be any doubt, however, that the vesicles do coalesce at 

 the polar end of the nucleus, for there the individual polar granules 

 frequently fuse to form composite granules, such as may be seen in 

 figure 12 (Plate 1) and figures 14, 15, 16, and 19 (Plate 2). 



The first indication of the longitudinal split which forecasts the next 

 mitosis was discernible at a stage such as is shown in figure 17. From 

 this stage on to the metaphase, however, the split was clearly visible. 



I believe that the evidence here presented furnishes very good 

 grounds for believing that the chromosomes do not lose their individ- 

 uality in passing through the so-called 'rest-stage' between the two 

 successive cell-di\'isions. 



d. The somatic Nuclei. 



Only slight attention has been given to somatic cells in connection 

 with the subject of the individuality of chromosomes, but some points 

 were noted which it seems worth while to record. The connective- 

 tissue nuclei within the follicle always divide by the indirect or mi- 

 totic method. The details are similar to those just described for the 

 spermatogonia, except that individual chromosome-vesicles, even for 

 the accessory, are less conspicuous — in fact, in my limited study of 

 these cells I have not recognized the accessory chromosome with 

 certainty. The only evidence of amitosis is a lobulated condition of 

 the resting nuclei ; that condition is a very characteristic one, but has 

 no more significance as to amitosis than the lobulated appearance of 

 the spermatogonia! nuclei. In the diffused chromatin-stages — telo- 

 phase, rest-stage, and early prophases — the polar granules appear, 

 coalesce more or less to form composite granules, and separate out 

 again just as they do in the spermatogonia. Furthermore, it is possi- 

 ble to find chromosomes in the telophases that exhibit all the chief 

 characteristics of the "selected" chromosomes. For example, in 

 Plate 9, B, figures 108, 109 and 110, are to be seen diffusing chromo- 

 somes with the characteristic features of one of the larger members 

 of chromosome-pair B. It would seem from this evidence that the 

 same morphological constitution of individual chromosomes persisted 

 even in these somatic cells. 



