Embryogeny of the Bryozoa. 271 
larve of Entoprocta and the vitelline mass of the larve of 
EKctoprocta. 
3. Lastly, the cloacal sac of the Entoproct larve is here 
replaced by a kind of sac with very thick walls, similarly pro- 
duced by an invagination of the exoderm, and placed near the 
centre of the oral surface. Very often a part of the wall of 
the sac rises up into a more or less elongated languette, which 
may be compared to the small pointed lobe placed at the side 
of the cesophagus in the Entoproct larve. In an Aleyont- 
dium allied to A. mytili this languette becomes so long as to 
project beyond the aperture of the sac. In this state it may 
be compared to the small lobe of the Entoprocta, while the 
sac in which it is lodged would represent the great semicircular 
lobe bearing the anus, which, in the Entoprocta, already sur- 
rounds the small one. 
These analogies are further comfirmed by the fact that in 
the larva of Tendra zostericola this sac, as in the Entoprocta, 
occupies the space included between the two branches of the 
intestine. 
Accessory Organs.—1. Here again I must mention an 
elongated comma-shaped organ (pyriform organ), which 
occupies the front of the oral surface, and is composed of a 
small mass of glandular nature opening into the fissure of 
the anterior oral surface and surmounted by a group of radia- 
ting cells (those which serve as a base to the vibratile tuft). 
It has been supposed that in this organ we have the homo- 
logue of the subbuccal appendage of the Entoprocta. Follow- 
ing the ideas put forward by Hatschek with respect to Pedi- 
cellina, it has been regarded as a rudimentary bud, which 
would convert the Bryozoan larva into a compound form. 
Upon this subject it will suffice for me to remark that the 
pyziform organ by no means occupies the same position as the 
subbuccal appendage of the Entoprocta: the latter is placed 
upon the aboral surface, beneath the mouth; the former is 
situated upon the oral surface, and in front of the buccal 
orifice. It would be well to name it the prebuccal appendage, 
‘in opposition to the name of subbuccal, which I apply to that 
of the Entoprocta. 
According to my investigations, the prebuccal appendage of 
the Ectoproct larvee disappears completely during the meta- 
morphosis; and the same is the case with the subbuccal and 
caudal accessory organs of the larvee of the Entoprocta. Hence 
I can only regard these accessory organs as belonging exclu- 
sively to the larval organism. ‘The observation of facts by no 
means confirms the hypothetical views adopted with regard to 
- them by the authors cited. 
