220 
appears. How, and why these sporadic dwarf males arise and again 
disappear, they cannot say. K ru ger therefore must have recourse 
to yet another theory in order to get out of the difficulty, and 
formulates it as follows: „Von den heute lebenden Gattungen sind 
Mitella und Scalpellum schon seit dem Obersilur bekannt. Es 
waren auch damals festsitzende Geschopfe, eine Lebensweise, die 
nach unseren Kenntnissen das Auftreten der Zwittrigkeit begun- 
stigt, so dass sie also schon zu diesen Zeiten wieder hermaphro- 
ditisch geworden waren und nun auf den heutigen Tag alle An- 
klånge an ihren friiheren Gonochorismus verloren haben.“ The 
last sentence evinces that also Kr tiger in reality is of opinion 
that the ancestors of the cirripeds had separate sexes. On the 
other hånd, he has here overlooked the faet that Scalpellum has 
males, and in all probability has not acquired them in later times. 
I have gone into details in this question, because the occur- 
rence of males has hitherto been undervalued in the discussion 
of cirriped phylogeny. We must agree with Kruger in maintain- 
ing that the primitive cirripeds have had separate sexes, and that 
their special biology, their fixed mode of living, makes us under¬ 
stand the disappearance of the male, and the development of her- 
maphroditism. 1 ) 
If the theory of the gonochoristic ancestors is correct, we shall 
have to accept a link between Calantica and Mitella, or rather a 
Mitella with male. So old this genus is that the chance of tinding 
it would seem rather problematic; my surprise therefore was great, 
as among the material, brought home by Dr. Mortensen from 
New Zealand, a Mitella- like species furnished with dwarf males 
really occurs. As it is shown in the table on pag. 226 this genus, 
Protomitella, links together the genera with males in a way that 
makes helping theories completely superfluous. 
Next to the parent form the genera in which the males have 
kept a high organisation most probably must be ranged. Among 
the recent genera Calantica has the highest developed males; in 
the male of Calantica Mortenseni described below, even some of 
the latera are present in the capitulum skeleton. According to 
*) Kruger in a letter to the author communicates that his embryologic 
studies have later on given results which are in better accordance with 
my theories than with Hoek’s. 
