VINE : BRITISH PALAEOZOIC CTENOSTOMATOTJS POLYZOA. 
si 
have gathered together, for the purpose of comparative study, all 
the Ctenostoinatous Polyzoa that was possible. The creation of 
the Genus Vinella by Mr. Ulrich for American forms has removed 
some of the difficulties that I had to encounter in my endeavour 
to group together systematically the peculiar forms which I have 
already described. Whether I am successful, or otherwise, in my 
endeavour remains to be seen. 
Independently of this there is no other group of organic forms 
known to me, excepting the stoloniferous Ctenostoinatous Polyzoa, 
with which Ascodictyon can be compared. I am not at all certain, 
however, that A. filiforme, A. siluri cense, or A. stellatum ever possessed 
deciduous cells, like MimoseUa, Valkeria, or even Vesicularia, yet in 
other respects the resemblance between the Palaeozoic and recent 
groups are most remarkable. 
Ascodictyon radiciforme, Vine. 
1882. Ascodictyon radiciforme, Vine, Quart. Jour. Geol. Soc, Feb., 
1882, p. 53, fig. 2. 
1884. ,, radiciforme, Vine, Ann. Mag. Nat. Hist., Aug., 
1884, p. 83, figs. 1, 2, 3 and 5 only. 
1881. „ radians, Vine (part), Quart. Jour. Geol. Soc. 
(provisional placement) p. 619, Nov., 1881, 
no figures. 
1887. ,, radiciforme, Vine, Yorksh. Geol. Polyt. Soc, 
vol. ix., p. 183-4, pi. 12, fig. 5. 
Zoarium, composed of elongated, root like processes, which vary 
in length from three quarters of a line, to a line. The radial pro- 
cesses are occasionally jointed, and unevenly developed around a 
common axis. The fusiform or tongue-like prolongations I have 
characterised previously as "vesicles" (Quar. Jour. Geol. Soc, 1882, 
p. 54), indicating by the use of the term a kind of cell, but I am 
not certain that these prolongations will bear that construction. In 
the free surfaces of some of these (vesicles ?) " excessively minute 
closely approximated pores," referred to by Nicholson in his descrip- 
tion of A. radians are present, and in parts where the stolon has 
broken away from the place of attachment, similarly minute pores 
