DAVIS: SPERMATOGENESIS. 91 



tends out free into the nucleus (Fig. 132). In this and succeeding 

 stages there is ahnost invariably a plasmosome in close proximity to 

 the monosome, usually in immediate contact with it, though in excep- 

 tional cases at some distance from it. 



During stage /the bipartite structure of the monosome is very marked 

 (Plate 3, Fig. 52; Plate 7, Figs. 133-138). One part, as in the pre- 

 ceding stage, can be distinguished by its more compact structure and 

 smooth contours; the other or elongated part is distinctly granular 

 with rough, ragged contours. As shown in the figures, it is usually 

 curved, and sometimes the two ends may come together so as to form' 

 a ring (Fig. 133). In some cases this ring may entirely surround the 

 non-granular part, while the two parts are more or less intimately 

 connected. 



The changes in the cytoplasm during the growth period are much 

 the same as those described in Dissosteira. 



G. Steiroxys trilineata. 



1. Autosomes. 



In this locustid the spermatocytes pass through essentially the 

 same stages as in the Acrididae, but owing to the small size of the cells 

 and relatively great amount of chromatin the material is much less 

 favorable for study. Figure 54 (Plate 3) shows the first stage (a) 

 of the primary spermatocyte, while Figure 53 is an imperfectly fixed 

 spermatocyte in the same stage. Owing to the chromatin being 

 shrunken away from the nuclear wall the concavity on one side of 

 the nucleus shows much better than on well fixed material. Figure 

 55 is that of a somewhat later stage (c), in which, as in the Acrididae, 

 fine chromatin granules are distributed along a much convoluted 

 spireme. In this species, however, the chromatin is in much finer 

 granules and more irregularly distributed along the thread than in any 

 of the Acrididae. In the next stage (d) the spireme has the usual 

 polar arrangement (Fig. 56) and at a little later stage (e) shows (Plate 

 5, Fig. 69) a more or less distinct longitudinal splitting. This splitting 

 is never as marked as in many of the Acrididae, but I believe there can 

 be no doubt that such a stage occurs. I have failed to find any evi- 

 dence of the side-to-side union of the spireme threads which Otte 

 "(:06) has found in Locusta. During stage /all traces of the longi- 

 tudinal splitting disappear owing to the fact that the chromatin 

 granules become broken up into finer particles and are irregularly 



