104 BULLETIN OF THE 
To my mind, the most significant difference between the two groups 
exists in the fact that the outpocketing to form the stomach arises from 
the oral end of the future alimentary tract in Endoprocta, and from the 
anal end in Ectoprocta. One is led to believe that in the ancestral form 
either two nearly equally important outpocketings from both the oral 
and anal sides existed, or that the two existing methods are remnants 
of a method different from either (such as the formation of the whole 
alimentary tract at once), or, finally, that the Endoproct condition repre- 
sents the ancestral one, and that the rectal evagination has secondarily 
become of greater importance in Ectoprocta, and that the oral evagina- 
tion has become less significant. Oka (90, pp. 134, 141) has recently 
asserted that in the polypide buds of the statoblast and adult colony of 
a Pectinatella of Japau (P. gelatinosa) the cesophagus and stomach are 
formed by one evagination, which acquires secondary connection with 
the rectum, This condition reminds one, then, of Endoprocta., I must, 
however, doubt the accuracy of Oka’s conclusions until more satisfactory 
evidence is forthcoming; the more so, since Pectinatella magnifica, 
Leidy, presents a method of budding exactly comparable to that in 
Cristatella and Plumatella, as my own sections show with sufficient 
clearness. 
The homology of the Ectoprocta and Endoprocta implies a homology 
of their larvae, and demands that the life history of the two groups should 
be directly comparable. 
It is well known from the researches of Hatschek (77) on Pedicellina, 
and of Harmer (85) on Loxosoma, that the surface of the larva which 
bears the mouth and anus, i. e. its oral side, corresponds with that of the 
blastopore. How, then, is the oral aspect of the Ectoproct larvee, which 
I have tried to show is opposite to the pole of the blastopore, to be 
homologized with this? 
The month and anus of the Endoproct larva undergo a rotation after 
the larva has settled, so that they come to occupy the pole opposite to 
that at which the blastopore was. This stage of the Endoproct larva 
is comparable to the whole larval stage of Ectoprocta. I believe the 
two stages to be homologous, and that, just as polypides are pre- 
coctously formed upon the Phylactoleematous larva, its larval digestive 
tract having dropped out from the ontogeny, so the mouth and anus of 
Gymnolemata are precociously formed on the pole opposite the blasto- 
pore, the primitive stage during which they existed at the blastoporic 
pole having dropped out of the ontogeny. 
It is well known from the works of Harmer (86) and Seeliger (89), 
