MUSEUM OF COMPARATIVE ZOOLOGY, 105 
that in Pedicellina, in which the metamorphosis of the larva has been best 
studied, the stolon arises from the base of the stalk — that is, at the pole 
where mouth and anus were first formed — at the pole of invagination. 
I have shown that this is true for Phylactoleemata, and probably for 
Gymnolamata. 
If the interpretation which I have put on Gymnolamatous ontogeny 
becomes confirmed, the larvæ and the budding areas will be homologous 
throughout all Bryozoa. The following diagrams will explain my idea 
of the relation of the different ontogenetic stages in the two groups. 
ENDOPROCTA. ECTOPROCTA. 
The left hand vertical series represents stages in the development of 
Endoprocta ; the right hand one, stages of Ectoprocta. The blastopore a 
is throughout turned upwards in the figures. Stage I. is in both cases ¢ 
young gastrula. Stage IT. is that of the free-swimming larva of Endo- 
procta, This stage is lost in the ontogeny of Ectoprocta, in which, by 
abbreviation of larval life, the free-swimming stage corresponds to the 
condition of the fixed Endoproct after it has undergone its rotation. 
This stage, or one slightly later, is shown in III. Both larvæ are fixed, 
the Endoproct by the blastoporic, the Ectoproct by the opposite pole. 
The position of the stolon, or of the first polypide of the colony produced 
by non-sexual methods, is represented at gm., near the blastoporic pole. 
