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present. A positive result of such an examination would set aside 
eventual doubt as to the justification of classifying Bergendalia with 
the fainily Stylochidae. One might say that, in regard to the 
arrangements of the eyes, the genus Neostylochiis discussed above 
forms a bridge over to the genus Bergendalia. It can then be added 
that the tentacle rudiments present in N. fulvopuntatus Yeri 
Kaburaki 1920 were so insignificant that they were not observed 
by the original describers (cf. Bock 1923, p. 346). 
The absence of tentacles in Limnostylochus is discussed above, 
and here I shall only emphasize that the presence of tentacular 
groups of eyes in at least two species of it indicates that tentacles 
have once belonged to the organization. 
I have here referred to and treated the tentacle question at 
length, because I bclieve that tentacles originally belong to the 
Stylochid-organization. But I am going also a step further. From 
the wide-spread occurrence of tentacular groups of eyes in Crasped- 
ommata and Schematommata must be concluded that this feature 
is very old and ancestral. The existence of two, well circumscribed 
groups of superficially located eyes at the sides of the brain ought 
to be interpreted as belonging to nuchal tentacles, the only kind of 
tentacles occurring in Åcotylea. 
To demonstrate how early the tentacular eyes and the tentacles 
really appear in the development, I might record the following case 
from my embryological researches. In young Planocera reticulata 
Stimpson just having reached the creeping stage, but with long 
larval appendages still remaining, the tentacles are already present, 
As they are well separated, it is already at a casual glance possible 
to distinguish without difficulty between the cerebral and tentacular 
eyes. Bach cerebral cluster contains four more deeply located eyes, 
each tentacular group only two eyes, superficially and laterally 
situated. In older embryos still included in the egg-shells the same 
disposition of the eyes is seen, and consequently the tentacular eyes 
can be recognized even when the tentacular projections are not 
clearly defined in the sections of preserved embryos. 
Lang has figured youngsters of Leptoplanids »aus dem Auftriebe 
(1884, Taf. 36), where cerebral and tentacular eyes can be distin- 
guished at a rather early stage. 
While marginal tentacles are confined to the Cotyleans, we find 
Vidensk. Medd. fra Dansk naturh. Foren. Bd. 79. H 
