260 
a critical representation of his Sertularian system, and in order 
to make it more coherent and easier to read, I shall give most of 
the quotations, on which it is based, as notes. Schneider at 
first states!) that my system, which is based on diversities in the 
opercular apparatus, cannot in any way stand together with that 
of the former authors who divide the genera mainly according to 
the arrangement of the hydrothecae in the branches”). He admits 
that at first sight it looks seductive?), but though he does not 
seem to have subjected it to a real test, he comes to the result 
that the older authors are right in the main, and that such a 
great systematic importance cannot be ascribed to the operculum 
in opposition to the characters formerly used"). — Schneider 
gives three reasons why he has not been able to admit my syste- 
matic characters. The first is connected with my assertion that 
there exists a certain harmony between the margin of the hydro- 
theca and the structure of the operculum, and that we, therefore, 
even in colonies which have lost their opercula, may be able from 
the structure of the former to draw a conclusion as to the character 
of the latter. Schneider thinks it possible, therefore, that a great 
deal of my statements are only based on this form of investi- 
gation5), in which he evidently has no confidence. However, I 
1) Levinsen begriindet auf den Bau des Opercularapparats seine von 
der åltern durchaus abweichende Systematik. Es ist nothwendig, zu 
dieser sofort Stellung zu nehmen; denn, falls wir sie acceptiren miissen 
ist eine Besprechung der frihern systematischen Angaben tiiberfliissig 
ja unmåglich" (p. 520). 
?) ,,Die åltere Systematik hielt sich, wenigstens in der rare an 
die Vertheilung der Hydrotheken an den Sympodien"' (p. 521). 
3) stilte den ersten Blick hat diese Eintheilung etwas Bestechendes" 
521). 
4) grin fragt es sich, ob wir der Deckelbeschaffenheit so hohe 
Bedeutung gegeniber den bis jetzt angenommenen Charakteren Zu- 
schreiben dirfen und ob letztere nicht doch wenigstens in den Haupt- 
zigen zu Recht bestanden. Ich ORDEÅ me mich dieser letzteren 
nschauung zuneigen zu miissen" (p. 5 ; 
5) ,Ueberhaupt mag Levinsen in den os BEER wohl oft zu sehr 
der åusseren Beschaffenheit der Hydrothekenmindung, die meist doch 
nicht immer auf eine bestimmte Deckelbeschaffenheit schliessen låsst, 
Rechnung getragen haben" (p. 522). 
