850 MR. A. W. WATERS ON 
as a communication pore was evidently the entire plate, it not 
being realised that there were not large pores, but only minute 
perforations. Reichert described and figured the plate as with a 
central perforation with 8-10 pores round it * (pl. iii. fig. 7), but 
this is not the case, as there is only one? perforation, and what 
Reichert took to be pores surrounding a central pore are really 
a cirele of cells, on the older side of the rosette-plate, with a 
relatively large round nucleus anda thin prolongation. The disk 
is thinner than the surrounding walls, as figured by Reichert 
(loc. cit. pl. iii. fig. 7). Sections and preparations of Zoobotryon 
from Naples, the Soudan and Wasin, enable me to add slightly to 
our knowledge of this species. 
By the rosette-plates of the zocecia the cells just mentioned 
often stain very darkly, so that no structure can be seen, but in 
other cases the plate is seen with all these cells in a semicircle = 
(PI. III. figs. 7, 8, 9, 12) pointing their thinner edge to the centre, 
or with them even raised to the one minute opening. Above, 
that is on the younger side of the rosette-plate, there are a 
number of cells, probably usually the same number as below, anc 
these also have long thread-like projections which pass to the 
opening to touch the projections of the under circle of cells, that 
is as if eight fingers from below were raised to touch eight fingers 
from above. From both sets of cells spread other cells in a 
more or less radiating manner, and to these mounds of cells the 
funicular or plasma-threads reach, distinguishable from the others 
by their elongated nuclei. These plasma-cords spread to all the 
organs of the zoarium. 
The layer of mesenchym-cells lining the zocecial walls (PI. II. 
fig. 10; Pl. IV. figs. 2, 3) spread to this mound of cells, and can 
be distinguished by the round cells and round nuclei from the 
funicular threads with their long cells and elongate nuclei. There 
is sometimes on one side a more or less semicircular cover over 
the circle of radiating cells, which it is difficult to understand, 
and they never occur in the early stages, and certainly they 
cannot be continuous all over or there would be no connection 
from the two sides. 
An ovum is often seen pretty near to the rosette-plate, so that 
it must move up to the distal end to be enclosed in the ovisac. 
When there is an ovum, and usually in the older zoocia, there is 
a considerable change in the funiculus near to the rosette-plate, 
as it has become granular (PI. IIT. figs. 10, 11), so that from this 
appearance the condition of the zocecium can be surmised. 
Nitsche$ spoke of the accumulation of cells over the rosette- 
plate as a “‘Pfropf” (plug or stopper), and Reichert mentioned 
* This figure was copied by Hincks, Brit. Mar. Poly. p. ix, fig. 4. 
+ Joliet, Bry. des Cotes de France, p. 31, footnote, says that Bowerbenkia has only 
one perforation. AsI have previously stated, Zoobotryon and Bowerbankia should 
not be generically separated. 
t This is the “joneturie” of Jullien, who describes a similar arrangement of cells 
to the joncturie of Schizoporella malusii Aud., ‘Cap Horn,’ p. 42. 
§ ‘ Beitr. z. Kennt. der Bryozoen,” Zeit. f. wiss. Zool. vol. xxi. p. 9 (1871). 
