46 H. E. JORDAN 
highly and more highly elaborated stages, respectively, in the 
same essentially lipoid granules, the complete series being repre- 
sented by the J-granules of the leg muscle, the large oval Q- 
granules of the leg muscle and the wing muscle, and finally the 
winged sarcosomes of the wing muscle. The latter may possibly 
represent remnants in mechanically modified form of these prob- 
able reservoirs of reserve food material. 
If one studied the leg muscle of the wasp only with alcoholic 
fixation, one would conclude that this muscle lacked sarcosomes. 
Reports of lack of sarcosomes in certain insect muscle may 
perhaps be explained on the basis of faulty preservation by the 
histologic technic employed. There may, moreover, most prob- 
ably be wide variations in the abundance of these elements cor- 
responding to phases of major metabolic cycles of an individual. 
The evidence to date suggests that all muscle contains the homo- 
logues of the sarcosomes of insect muscle in at least some slight 
degree of elaboration. That the sarcosomes of the wing muscle 
are not mitochondria, as has been suggested (Thulin,?’ Bullard’), 
is quite clear from their size, shape, and resistance to the usual 
mitochondrial solvents. It is difficult to see how Meigs® was 
led to the erroneous conclusion that in the wing muscle of the fly 
the sarcosomes are “almost certainly granules of coagulated 
sarcoplasm; there is nothing similar to be seen in preparations 
of fresh muscle” (p. 89). Contrary to this statement, nothing 
could be simpler than the isolation of these granules by teasing 
fresh wing muscle of fly in Ringer’s solution. 
c. The accessory disc 
This dise (‘N-stripe’) was first seen by Briicke! in 1858 in the 
leg muscle of Hydrophilus piceus. It has received careful study 
at the hands of Rollet,?* who first disposed of Retzius’' claim that 
it consisted of J-granules. Rollet interprets it as consisting of 
essentially the same substance as the dark disc; it is said to be 
anisotropic like the Q-dise and the telophragma, but more 
weakly anistropic than Q. 
The accessory disc is very conspicuous in the leg muscle of the 
wasp, the elater, and the grasshopper. It consists of modified 
