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SIDNEY F. HARMEK 
of the surfaces of the Polyzoa, hut has based his conclusion 
entirely on a study of Phoronis. When we add to these 
facts the position of the nerve-ganglia and of the pole-cells of 
the mesoblast, I consider that it is impossible to resist the 
conclusion that Phoronis in no way gives an explanation of 
the anatomy of the Polyzoa. 
Before passing to a consideration of the larvae of the 
Ectoprocta it will be necessary to examine the statements 
of Uljanin (5), van Beneden (1), and Barrois (13, 29, and 
33), with regard to the metamorphosis of Pe dice 11 in a. 
Uljanin’s statements have already been shown by Barrois (13) 
to be based on the supposition that adult calyces fallen from 
their stalks were larvae which were commencing to undergo 
their metamorphosis. Van Beneden's account and those of 
Barrois differ in fundamental particulars, and although it is 
conceivable that there may really exist a great difference in the 
post-larval stages of various species, it is very possible that van 
Beneden’s account is incorrect. According to this observer 
we have in Pedicellina a metamorphosis of the simplest 
kind ; the larva fixes by its sucker, this extremity growing out 
into a stalk, and a circlet of tentacles appears on the inner side 
of the ciliated ring, which is subsequently atrophied. If this 
account is correct (and it is not impossible) the first individual 
of the colony is the fixed larva. 
Barrois’s account (33) of the post-larval changes (in the 
Entoprocta in general) is the following : — (i) The larva fixes 
by its oral face ; (ii) the vestibule sinks to the interior, and 
becomes divided into several portions : (a) an “ inferior’' por- 
tion corresponding to the outer part of the vestibule, that car- 
rying the ciliated ring; this gives rise to the foot-gland, 
permanent in Loxoso m a, temporary in Pedicellina; ( b ) a 
“ superior” portion, the deeper part of the vestibule ; and (c) 
a middle portion, forming a mass of globules filling the stalk. 
The portion described as b remains attached to the alimentary 
tract, which twists round (the details of this process are not 
given), so that the concavity of its flexure is ultimately directed 
towards the free surface of the fixed larva instead of towards 
