78 vixe: carboniferous and permian polyzoa. 
pL ii.) will show the justness of this remark. There is a close affinity 
of this with that of Hall's Genus Prismoijora, or rather with the 
Carboniferous species found in the Lower Carboniferous Rocks of 
Kakaskia and Tateville. U. S. Am. In the Scotch beds the size 
of the branches vary so much, that certain forms may be conveniently 
characterised as a variety of Etheridge's more delicate species. In 
the Yorkshire shales there is a still greater difference when fragments 
are drawn to scale. For convenience, therefore, I think it will be 
best to give a varietal name to one of the Yorkshire forms. 
GONIOCLADIA CELLULIFERA, Eth. Jun. 
var, robusta, pi. iv., fig. 17. 
The fragments of this variety are similar to the above, only the 
branches are more compressed, robust, and the distances between the 
Zooecial apertures greater. In pi. ii., (fig. 14), an example of the 
more delicate species, as found at Hurst is given, which when com- 
pared with the example, (fig. 15), from Gare Scotland very little 
difference is observable in the size of the branches. Fig. 17, however, 
illustrates the robust character of the form depicted. All are mag- 
nified about 30 times. 
Distribution. Scotland : Type sp., (Eth. Jun.), Braidwood Car- 
luke. The species is found in several other localities. Yorkshire : 
Hurst and Richmond, forma robusta, Vine, Hurst. In my North- 
umberland and North Lancanshire material minute fragments have 
been detected, but are very rare, and besides those named I have not 
found it in any other English locality. 
Minute structures of Cystodictya and Gonigcladia. 
In dealing with the minute structures of our British Cystodic- 
TYONiDyE, I shall depend, more particularly, on my own investigations, 
rather than on those of others. At the same time it would be 
unwise as well as unjust to the authors, if I did not refer to two 
special papers on the same subject. In founding the family Mr. 
Ulrich says : — In the proposed family Cystodictyonidw we have a 
combination of characters not occurring in any other group, while on 
the other hand, not one of these can be said to pertain to this group 
alone, nor to be especially distinctive."* After going over the details 
* Journ. Cin. Soc. Nafc. Ilist., vol. vii., p. 35, 1884, 
