STRUCTURE AND DEVELOPMENT OP LOXOSOMA. 317 
canal is the same as in Loxosoma, the stomodseum being 
homologous in the two cases; Repiachoff’s “sucker” ( v , 
fig. 22) represents the vestibular invaginations of Loxosoma, 
as has been pointed out by Barrois (33). The identity in 
general relations between these structures in Loxosoma 
after their median fusion (fig. 45, v) and the “sucker” of 
Repiachoff’s Tendra (fig. 22, v) is in fact very apparent. 
The hypoblast cells budded off from the front of the archen- 
teron represent, on my view, not Hatschek’s dorsal organ, 
but the cells which I believe to be proliferated from the larval 
stomach (long after the development of the dorsal organ) and 
to enter into the composition of the bud. The cephalic 
ganglion of Loxosoma would in this case be represented 
by the epiblastic invagination x of fig. 22, the relations of 
this to the budding organ being possibly different from that of 
the same structure in Cyplionautes, although this does not 
absolutely follow from the figure. 
Barrois (23), in describing the development of Lepralia 
unicornis (Cheilostomata), confirms Repiachoff’s account 
of the invagination of the archenteron, and further calls 
attention to two lateral mesoblastic bands at the sides of the 
blastopore. In a subsequent paper on the metamorphosis of 
Ectoprocta (33), Barrois has suggested, as mentioned above, 
the homology of his “ internal sac,” Repiachoff’s “ sucker,’’ 
previously described by Barrois himself (13) as “ stomach,” 
with the vestibular invaginations of Entoprocta, although 
his identification of other parts appears to me unsatisfactory. 
During the metamorphosis, the larva is attached by the 
evagination of this “ internal sac,’’ and a complicated process 
takes place, resulting in the formation of the first polypide of 
the colony. From the organ described in Balfour’s ‘ Text- 
Book’ as the “ ciliated disc,” and which one might suppose to 
correspond to the foot-gland of Loxosoma (this view is con- 
troverted by Barrois) develops an invagination which forms 
the polypide. The eversion of the “ internal sac ” during 
fixation does not seem to me to preclude the possibility of its 
homology with the vestibular invaginations of Loxosoma; 
