90 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
cies, but the longitudinal split often shows with almost diagrammatic 
clearness. ‘The chromatin granules are large, and can be clearly seen 
arranged in pairs at nearly regular intervals along the linin thread. 
Figures 49 and 50 show the spireme as seen from the distal pole, while 
Figure 51 shows a cross section of the loops just below the point where 
they are attached to the nuclear membrane. In addition to the mono- 
some, the cut ends of fifteen or sixteen threads can be distinguished in 
the section, which is the number we should expect to find, since there 
are sixteen autosomes in the spermatogonia. In stage f (Fig. 52) 
the loops open out as in the preceding species and tend to take a pe- 
ripheral position. ‘The chromatin granules break up into still finer 
particles, and the longitudinal split becomes less evident. However, 
in this species there is no such obliteration of the longitudinal split 
as in Dissosteira, but throughout stage f it remains fairly distinct. 
2. Monosome. 
The history of the monosome during the growth period is quite 
different from that in Dissosteira, but shows many points of resem- 
blance to Melanoplus. However, owing to its greater size the changes 
in the monosome can be followed to much better advantage in this 
species. During stage a (Fig. 47) the monosome is an elongated, deeply 
staining, homogeneous body enclosed in a separate vesicle. Rarely, 
it is divided by a transverse constriction into two nearly equal parts. 
In stage b there is little change in the appearance of the monosome, 
but, as in the preceding species, it becomes enclosed within the common 
nuclear membrane. In the following stage (c) (Plate 7, Figs. 125-128) 
the monosome forms a more or less flattened plate, in which several 
small vacuoles can usually be distinguished. A little later (stage d) 
it begins to elongate (Figs. 129, 130) and a process grows out from 
one end. In the following stage (e) this process may reach a consid- 
erable length (Figs. 131-132). During this stage the bipartite struc- 
ture of the monosome becomes evident. One part is a flattened, 
rounded or somewhat elongated body with smooth contours, and con- 
tains numerous small vacuoles. The other part is of nearly the same 
size but greatly elongated and distinctly granular. In fact it strikingly 
resembles the spireme, except that the chromatin granules age larger 
and crowded together more closely. When the monosome lies at 
some distance from the distal pole it is connected with it by means of 
this elongated part (Plate 3, Fig. 49; Plate 7, Fig. 131). However, 
if located near this pole, as is usually the case, the elongated part ex- 
et oe oa 
