12 
the ooeciiim and the wall of the zooecium. It commences as two 
distinet processes from the lateral walls which finallj coalesce. In 
Fl. {Memlr.) flustroides , whose ooecia project on the zooecial sur- 
face this band suhequently inereases in height and at last covers 
the whole front part of the ooecium. In the family Farciminariidae 
the construction and the position of the ooecia are mainly the same 
as in Flustridae, but the ooecia always project on the surface of 
the zooecium. In the group of species represented by Fare. magna 
the superior part of the ooecium is on each side covered hy a 
little vaulted calcified plate projecting from the lateral wall and 
seated hetween the ooecium and its covering memhrane. 
To this type we provisionally refer a numher of ooecia found 
in very different families and as far correspondent with the ooecia 
in the Flustridae that they are seated internally hetween two zooe- 
cia and are coalesced with an incompletely developed distal wall. 
For want of suitable material I cannot at present give any infor¬ 
mation about the membranous or muscular parts of these ooecia. 
While the covering zooecia in a numher of forms (f. i. Micropora co- 
riacea, M. perforata, Lepralia sincera, Catenicella pulchella, C. pu- 
silla, C. gracilis, C. formosa etc.) are autozooecia, in most cases 
they are kenozooecia. Ooecia covered by kenozooecia are found in 
most members of the family Diazeuxidae, and besides within a 
number of different families, namely in the Bicellariidae {Didymia 
simplex, Fueratea chelata, Bicellaria infundihulata), Cellulariidae 
{Menipea crystallina, M. cervicornis), Crihrilinidae {Cribrilina punc- 
tata, Cr. Gattyae), Mucroyiellidae {Mucronella diaphana, M. abyssi- 
cola) and Catenicellidae (Catenicella plagiostoma, v. setosa, C. ventri- 
cosa, C. margaritacea etc.). In all the here named forms the zooecial 
operculum when opened to a certain extent closes an opening whose 
proximal margin is the hinge-line of the operculum while distally 
it is limited by the free ‘margin of the ooecium. It is the outer 
opening of a space which can be regarded as a fore-court common 
for the zooecium and the ooecium and which we will name an 
atrium. While Jullien has found no polypide in the ooeciferous 
