80 vine: carboxiferous and permiax polyzoa. 
however, a faint similarity in the bars, and also in sections of the 
margins of the Zoaria, but beyond this there is no noticeable feature 
common to the two types. In the transverse section of C. parallela 
(tigs. 12, 13, pi. i,) the opposite leaves fit into one another V shape, 
but the bases of the cells do not touch the neighbouring cells, for, as 
indicated in the sketch, a delicate interspace intervenes between them. 
These spaces it will be convenient to call Endosarcal passages." 
The position which the superficial bars occupy in the Zoarium is in 
a line with the cells. The bars are, below a certain depth, structure- 
less, and it appears to me that they are simply a calcification of the 
Ectocyst, which, as in recent species of Polyzoa, have been derived 
from the Endocyst of other cells. In the margins of the Zoarium 
the formation of the newer Zooecia may be detected in all stages of 
development, produced by repeated gemmation, and I believe that to 
a large extent the vesicular character of the interspaces and margins 
of Cystodictya are really sections of newer, or the calcified remains of 
cells in process of formation. If so, then we have no Coelenterate 
character to deal with in these older Polyzoa, but rather characters 
that are new to us probably, but nevertheless explainable if the Coene- 
cium of recent species of Polyzoa be studied and compared. On this 
head, however, Mr. Ulrich very justly remarks, " Tangential sections 
passing through the ' immature' region of the Zoarium show that the 
Zooecia are ranged in longitudinal series between vertical plates, to 
one of which (see figs. 4, 5, 6, pi. i,) they are latterally attached, 
while the intervening spaces are occupied by irregularly shaped 
smaller cells. Nearer the surface the latter are no longer to be 
determined, being here filled by a secondary deposit."'-' In trans- 
parent portions of recent Flustra and Carhasea, better in the last- 
named, the ccenecium is best studied on the margins of the Zoarium, 
and here I find, that though newer cells are in processes of formation, 
by gemmation of course, in none of the partly-formed ones are there 
any indications of polypides until after a certain stage is passed. In 
the growing branches of Zoohotryon pellucida Ehrenb. the ccenecium 
may be studied far more advantageously, if the specimens be mounted 
in glycerine, and the action of the Endocyst, in the formation of buds 
* Jour. Cincin. Soc. Nat. Hist. 188i (op. cit.) pp. 35-36. 
