436 GUSTAF FR. GOTHLIN 
As we know, it was for a long time a matter of dispute whether 
a nervous system in the morphological sense existed at all in the 
ctenophores or not. In this connection I will only refer to the 
results of investigations and opinions that have been put forward 
in later times, more precisely from 1880, when Chun’s and R. 
Hertwig’s fundamental works on the histology of the etenophores 
were published. Among later investigators the most negative 
position is taken up by Samassa (’92, pp. 229-230), who rejects 
the idea of a nervous system in ctenophores, in general, but makes 
an exception in the case of Beroé in the following words: ‘‘ Das 
nichste (i.e., highest?) Stadium stellt Beroe dar; hier sind Epi- 
thelzellen der Basalpolster aus ihrem epithelialen Verbande aus- 
geschieden und haben sich zu Fasern umgestaltet, welche die 
Basalpolstern untereinander verbinden. Sie besitzen physiolo- 
gisch offenbar nervenihnliche Function und, da sie auch histolo- 
gisch den Charakter selbstiindiger Nervenfasern erlangt haben, so 
stehe ich nicht an, sie als soleche zu bezeichnen.”’ 
‘The presumed inhibitory nerves ought, however, to begin with 
receptors at the surface of the animal, probably by preference at 
the edge of the mouth, the polar fields, and presumably also at 
the meridional rows themselves, and to extend to the basal con- 
nections between the swimming plates. R. Hertwig (’80, pp. 88- 
91) has actually described—even in Beroé—tissue elements, 
situated subepithelially in the gelatinous substance, which he 
explains as nerve cells with long processes. He found endings of 
these processes in, among other places, the surface epithelium 
and in the muscle cells of the gelatinous substance. 
Hertwig’s communication of a subepithelial nerve net in cteno- 
phores has been confirmed by A. Bethe in preparations obtained 
by vital methylene-blue coloration. Nerve fibers ending in 
smooth muscle fibers in the gelatinous substance of Beroé are 
also described and reproduced by K. C. Schneider (’92, p. 448). 
On the other hand, I have been unable to find in the literature 
any statement to the effect that nerve fibers could be followed 
through the gelatinous substance to the meridional rows. In 
connection with this question it is of interest, however, to note 
2 Added by the writer, so that the context may be understandable. 
