92 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
distributed along the spireme thread, which at this time has a consid- 
erable size. ‘Throughout this stage the spireme retains its distinct 
polarity, although, as in the Acrididae, the loops tend to assume a 
peripheral position. 
2. Monosome. 
The monosome during the early part of the growth period (stage a) 
is inclosed in a separate vesicle lying next the concave side of the 
nucleus, but always separated from the nuclear wall by a thin layer of 
cytoplasm (Plate 3, Figs. 53, 54). At this time the monosome usually 
appears as a rounded, deeply staining, homogeneous mass, but on 
strong decolorizing shows a distinct granular structure. ‘The whole 
appearance is strikingly like that of the same element in the resting 
spermatogonium. Later the monosome becomes flattened, so that 
it has the shape of a plano-convex lens, the flat side being applied to 
the exterior of the nuclear membrane (Fig. 55). In the following 
stage (d) the monosome (Fig. 56; Plate 7, Fig. 151) has become en- 
closed within the nuclear membrane. It now forms a deeply staining, 
somewhat elongated and flattened element closely applied to the nuclear 
wall and connected at one end with the distal pole; but it soon becomes 
converted into a U-shaped body by the development of a longitudinal 
split (Figs. 152, 153). In stage f the monosome (Fig. 154) forms an 
irregular, vacuolated plate, the arms of the U having fused along their 
entire length. 
In the spermatocytes of Steiroxys the mitochondrion has a very 
different form from that found in the Acrididae. Instead of being 
distributed irregularly through the cell, it is collected into a rounded 
mass, which lies in the cytoplasm at the distal pole (Plate 3, Fig. 56). 
This body, which is distinguished from the surrounding cytoplasm 
by its deeper stain, is very finely granular and usually shows a still 
more deeply staining layer around the periphery. Sometimes the 
entire body is composed of several deeply staining rings separated by 
lighter areas. A very similar condition of the mitochondrion has 
been described by Otte (:06) in Locusta. In addition to the mito- 
chondrion an interzonal body is present at the distal pole and appears 
essentially the same as in Dissosteira. 
