SILURIAN SPECIES OF GLAUCONOME., 331 
representative of its class. Itis the head of an important genus ranging 
from the Bala or Caradoc beds to the latest Carboniferous. Although 
the earliest of its kind, this species was of strong robust growth, 
exceeding in size the species of later date. Large fragments of it 
are frequently found in the Bala beds. ‘hat so fragile an organism 
should be found in an almost unbroken condition suggests the fact 
that the sediment, from whatever cause, must have accumulated 
very rapidly around it. 
Locality. Fairly abundant in the Bala beds of Glyn Ceiriog, 
Denbighshire, and Cefn Coedog near Corwen. 
We would slightly enlarge the characters of the original Dudley 
species as follows :— 
GLAUCONOME pistTIcHA, Lonsd. 
Glauconome disticha, Goldf. Petref. Germ. Tab. 64, fig. 15 ; Silurian 
Syst. pl. 15. fig. 12. 
Pinniretepora Lonsdaler, D’Orb. Prodr. de Pal. i. p. 45. 
Sp. char. Zoarium branched or pinnate, the branches diverging 
at a sharp angle from the main or central stem. Stem rooted by 
a strong base. Zocecia both on stem and branch. When fully 
developed, two rows of quadrangular or pyriform cell vestibules 
arranged longitudinally on stem and branch, on either side of a 
strong keel, which is nodulose when perfect. ‘Three rows of cell- 
openings may often be seen on the main stem. Aperture of cells 
unknown. 
Obs. In addition to the features already described in this species 
there is an antique arrangement of the cells that is unlike anything 
seen in modern types. There is another detail worth mention. In 
the cells of Membranipora membranacea and the Flustrid generally, 
the cell is entirely bounded by its own wall. A perpendicular line 
drawn through the end walls would enclose the cell and its contents. 
In the Paleozoic types, lines similarly drawn would cut off the true 
cell from the area, the cell being buried beneath the area operated 
upon. 
Recurring to the present classification of the Polyzoa, it is 
evident to a large extent that the divisions are founded upon recent 
types. Of the three suborders (i) Chilostomata, (11) Cyclostomata, 
(iii) Ctenostomata, the latter is unknown to us in a fossil state. 
We know of no genera or species within the British area, in either 
the Cainozoic or Mesozoic epochs, that may not be included in the 
first or second of these divisions if shghtly modified. When we pass 
to the Paleozoic forms, it is different. Here we meet with types of 
Polyzoa essentially different, in which the cells are devoid of stomata, 
either subterminal or terminal, being concealed beneath what we 
have called the vestibule. This is often very large and filled with 
matrix. The concealed stomata may be shown in sections of species 
of Pitlodictye and Ceramopore. ‘To meet the case of these older types 
of Polyzoa, we propose a new suborder which shall have special 
reference to the cell and stomata. As yet we have no clear evidence 
