82 VINE : BRITISH PAL EOZOIC CTENOSTOMATOUS POLYZOA. 
stems are clearly defined and very transparent. It will be noticed 
that the number of cells in each of the whorls are most irregular, 
and some of those left out in the drawing" contain only two, three, 
and four cells. All the whorls are connected by hollow fiiimentoug 
threads, the walls of which are about one-fourth the diameter of the 
thread on either side, whilst the central part, two-fourths of the thick- 
ness, contains the dark brown mass so frequently referred to in my 
various descriptions. Unless the cells are broken there is not so far 
as I can see, any other opening or aperture through which the poly- 
pide of these old-world organisms protruded. This evidence I regard 
as pretty conclusive that we are dealing with Ctenostomatous rather 
than with Cyclostomatous Polyzoan remains. In plate IV. I have 
shown several cells in process of formation, (really matured cells, 
belonging to Ascodictya, are almost if not wholly unknown to 
me) ; and if the readers will turn to vol. ii. of Hincks' British Marine 
Polyzoa, plates 74, 75, and 80, he will see illustrations of many of 
the recent Ctenostomatous Polyzoa likewise figured, showing matured 
as well as unmatured cells. There is no recent species of the Ctenos- 
tomata that I have studied more closely than the Mediterranean 
form, known as Zoobotryon pellucida, Ehrenb.j and as far back as 1879 
I made drawings of the slowly growing stem of this Polyzoon, in the 
hope that I might be able to throw some little light upon the growth 
of buds on the stems of the Carboniferous Ascodictyon Youngi, but 
it was not till after my second British Association Report on Silurian 
Polyzoa was published that I ever dreamed of referring Silurian or 
Carboniferous species to the Ctenostomatous group. At that time I 
had a somewhat timid dread of " Authority," which, I am happy to 
say, is now slightly abated, and since then I have treasured up many 
fragments of shell and Crinoid stems from the Wenlock Shales, on 
which Ascodictya and Rhopalonaria were abundant. Had the forms 
which I have already referred to been found in a living, or even as 
semi-fossil remains, that is to say in any of the higher Tertiary form- 
ations, I really believe that the discoverer of anomalous organisms 
* Altogether there were eight whorls, similar to those drawn, on the piece of 
shell which measured nearly a quarter of an inch square, 
t Thanks to Mr. Waters, Miss E. C. Jelly, and Dr. Pergens, I have always 
been kept well supplied with this species preserved in alcohol. 
