32 H. E. JORDAN 
Certain additional facts should here be recorded regarding the 
sarcosomes. When arranged in single series between adjacent 
sarcostyles, the long axis of these sarcosomes is generally at right 
angles to the long axis of the sarcostyles; when in double series, 
their long axis is in general parallel with the long axis of the 
sarcostyles. Certain irregular forms also occur, wedge-shaped 
(fig. 24), crescentic (possibly collapsed ovals), fusiform, and 
stellate forms (fig. 48). Transverse sections reveal the fact 
that all types, and taken as a whole the vast majority, of the 
sarcosomes have wing-like processes which almost completely 
ensheath the sarcostyles (figs. 45 and 48). In this material no 
very small spherical sarcosomes occurred. The sarcosomes of 
the wasp’s wing muscle were preserved in all of the fixing fluids 
used (Flemming’s fluid, 95 per cent alcohol and 10 per cent 
formalin). They must therefore contain in large measure 
something in addition to lipoids. Their irregular winged form 
appears due to secondary mechanical modifications resulting 
from the pressure exerted by adjacent sarcostyles. The evidence, 
Fig. 10 Longitudinal section of portion of leg-muscle fiber of a grass hopper. 
The fiber passes abruptly from a condition of relaxation to one of contraction 
at point A, where a contraction band can be seen forming by process of fusion of oppo- 
site halves of two successive dark dises against the involved telophragma. The 
telophragma is no longer discernible at the phase of contraction shown at A, due 
probably to its having become stretched by the horizontal tension at this level to a 
degree of delicacy beyond the limits of microscopic vision. The formation of the 
contraction bands below A has effected a true reversal of striations as regards a 
deeply staining constituent of the dark disc. Flemming’s fixation, iron-hema- 
toxylin stain. > 900. 
Fig. 11 Transverse section of a wing-muscle fiber of the wasp. Nuw., periph- 
eral nucleus; other nuclei are scattered throughout the diameter of the fiber; 
S., sarcolemma. The light areas represent rows of adjacent sarcostyles; the 
dark areas, intervening sarcosomes. Flemming fixation, iron-hematoxylin stain. 
x 400. (The photomicrographs for figs. 11, 12, and 13 were made by Mr. William 
S. Dunn, Cornell University Medical School, New York.) 
Fig. 12 Small area from figure 11 more highly magnified. The circular out- 
lines of the sarcostyles are clearly shown; also the enveloping wing-like processes 
of the intervening irregular sarcosomes. Nu., nucleus. > 900. 
Fig. 13 Longitudinal section of portion of fiber of wasp’s wing muscle show- 
ing the lightly staining sarcostyles and the intervening dark sarcosomes. The 
conspicuous transverse lines represent the telophragmata. Z, telophragma; M, 
mesophragma; Sc, sarcosome; st, sarcostyle. > 1300. 
