(Sah) 
found to be connected with each other by means of very delicate 
fibrillae, which are running parallel to the myofibrillae. This could 
be stated in many cases with great clearness. In some cases these 
fibrillae were straight, in other cases more or less undulating. In 
fig. 6a a longitudinal section through the muscular plates (cut 
obliquely) is drawn greatly enlarged. The small dots and fibrillae 
are easily to be seen. 
In transverse sections the same rows of fibrillae and black dots 
were also to be seen, and here they are seen to be distributed 
more or less regularly on the muscle-plates (fig. 65). At both ends 
of the black dot here too a delicate black line may be seen, extending 
for some way along the muscle-plates but then being lost to view. 
By playing up and down by means of the micrometer screw of the 
microscope in cross sections too a longitudinal fibril may be made 
out extending upwards and downwards from the black corpuscle; 
this fibril is identical with that, which in longitudinal sections was 
seen to run parallel to the myofibrillae and to connect the black 
dots of a longitudinal row with each other. 
So we find here in the muscle-plates of Amphioxus an apparatus, 
which brings the anisotropous dises of the same muscle-plate in con- 
nection with each other, which seems to be distributed with some 
regularity over the whole muscle-plate, and which gives the staining 
reaction of the neurofibrillae. Although I could not find the connection 
of these fibrillae with the motor nerves, still these facts seem to 
point to the conclusion, that we may regard these fibrillae and their 
knobshaped thickenings at one side of the anisotropous discs as 
representing the real innervation-apparatus of the striped muscle-fibres. 
Sometimes I saw one of the longitudinal fibrillae near the place 
of attachment of the myofibrillae to the myosepts bend off from 
the muscle-plate; but it was lost almost immediately between the 
myofibrillae in the neighbourhood and could not be traced any farther. 
When we consider however the constant position of the small knob- 
shaped thickenings at one side of the anisotropous disc, the fine often 
undulated connecting fibrillae, the dark-purple tinction with chloride 
of gold (Nachvergoldung Apituy) so characteristic for neurofibrillae, 
then, I think, it is difficult to avoid the conclusion that they are 
neurofibrillae. 
This seems to me to be important from a general point of view. 
Although the structure of the striped muscular tissue of Amphioxus 
differs largely from that of the higher Vertebrates, yet the same type 
of cross. striation, that is, the same structure of the myofibrillae, is 
present in all, 
