(950) 
Now Ap<ray and Rurrimi') were able to demonstrate in homo the 
existance of “ultraterminal”’ nerve-fibres, that is to say nerve-fibres 
which grow out from the branching and thickening of the motor 
nerve known as “endplate”, and enter the muscle-fibre (this could 
not be made out with absolute certainty) pass through it and in 
many cases are connected with other endplates. Only a few cases 
are described but they are sufficient to show that the so-called nerve 
end-plate is not always to be considered as the real termination of 
the motor nerves. 
The following observations seem to point to the same conclusion. 
The thin muscle-plates of Amphioxus (fig. 6@) present in longi- 
tudinal sections a beautiful cross striation. Each isotropous disc (#) 
is divided into two dises by a delicate, but distinct membrane of 
Krausr; each anisotropous dise (g) is composed of two discs, separated 
by a thin layer, that takes but a faint stain with chloride of 
gold, the median disc of Hersen. In the middle of this transparent 
portion there is sometimes to be seen an extremely deiicate line, 
the membrane of HexsenN. 
The membranes of Krause form, as is known, crossnets, which 
bring the fibrillae of the entire muscle-plate in connection with each 
other. In the adult animal real muscle-cells are not to be distinguished, 
there are only the thin flattened muscle-plates to be found, which 
however in hardened specimens sometime appear to be broken up 
into rows of flat bundles of fibrillae. This is nothing but an artefact. 
In longitudinal sections of Amphioxus in which therefore the muscle- 
plates are cut in the same direction, but mostly appear not as plates 
but cut obliquely as bundles of muscle-fibres (fig. 67), there are to 
be found, in case the sections are coloured after the chloride of gold 
method, in many places just there were the anisotropous and isotropous 
dises meet, minute black dots, or small corpuscles; seen under a 
microscope of the highest magnifying power these dots appear as very 
delicate cross lines, thickened in the middle, running just between 
g and 7. In these discs belonging to the same muscle-plate these 
dots are lying in adjoining discs one just beneath the other, so that 
rows of black dots running parallel to the myofibrillae are formed. 
In each muscle-plate such longitudinal rows seem to be distributed 
with some regularity. These black dots were always found only 
at one side of the anisotropous disc, and, so it seems, always at 
the same side of g, viz. at that turned caudal. The black dots lying 
in the same muscle-plate in the same longitudinal row, are often 
1) Rivista di Patologia nervosa e mentale, Vol. V fasc. 10, 1900. 
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