LOWER CARBONIFEROUS BRYOZOA 
Fig. 101 Goniocladia cellulifera (Etheridge, 1873b). Line drawing of 
external features of BMNH PD9704; scale bar = 1 mm. 
Fig. 102 Goniocladia cellulifera (Etheridge, 1873b). Line drawing of 
| protion of a reticulate colony of BELUM K2164; scale bar = 1 mm. 
examined measured 19 x 12mm. Branches are bifoliate, laterally 
‘flattened, straight, and maintain a constant width along their length 
except prior to division when a small increase in width occurs. 
Branches divide, at angles of 30° to 70°, at short regular intervals. 
-Coalescing of branches produces a regular pattern of pentagonal, 
“nexagonal, or polygonal fenestrules upto 4.9mm long by 3.4mm 
wide. Branch division frequently produces three branches 60° apart. 
_ Dissipiments are absent. 
Branch cross-sections are narrow with a pyriform to rhombic 
outline. The barren reverse surface is well rounded with a faint to 
“distinct longitudinal carina while the celluliferous frontal surface is 
divided by a strong narrow angular median keel. These ridges are the 
_pxternal manifestations of the internal median wall. 
| Autozooecial apertures are arranged in quincunx in four to seven 
 ongitudinal rows, either side of the median ridge. Autozooecial 
"ipertures are large, circular to rarely oval in shape. Proximal lunaria 
"ire developed around most apertures. The size and thickness of the 
_junaria decreases towards the median keel. Interapertural areas are 
smooth and featureless. Autozooecial apertures are regularly spaced 
within longitudinal rows. Interapertural spacing decreases towards 
he median keel from five to two diameters apart (Table 31 and Fig. 
103). 
161 
Colonies arise from stout holdfasts up to 13mm in width. Initial 
colony growth is encrusting where autozooecial apertures are large, 
circular in shape and closely spaced. From this adnate portion three 
to six erect branches arise, which either remain isolated as erect 
eschariform colonies or anastomose to form reticulate colonies. 
Internally branches are divided by a thin, straight compound 
median wall. It is composed of a dark coarse central layer sur- 
rounded by a thin pale laminated layer. Autozooecia are budded 
from this wall. In the endozone autozooecial chambers are long, 
narrow, recumbent, and the thin chamber walls are shared. In 
transverse section they are semi-circular to pentagonal in shape. 
Autozooecial chambers curve distally from the median wall at 
angles of between 60° and 20°, and they diverge away from each 
other so that in the exozone they are isolated. The thickness of the 
exozone is greatest at the widest portion of the branch, where 
vestibules are oriented at a high angle to the zoarial surface, and 
decreases in the autozooecial rows towards the median keel, where 
vestibules lie at a low angle to the zoarial surface. 
Small hemispherical vesicles 0.01 to 0.03mm in diameter are 
commonly found between autozooecial chambers. They are thin- 
walled, irregularly shaped and may be infilled with stereom in the 
endozone. 
Table 30 Measurements of Goniocladia cellulifera in mm. N=18. 
NM x Mn Mx CVw CVb 
BWI 137 1.47 0.83 2.30 7.38 5.00 
BW2 44 0.69 0.33 0.98 9.03 6.21 
Zl 62 6.30 4 9 13.06 12.01 
Z2 161 3.90 2 6 SA 9.41 
AD 180 0.12 0.10 0.20 11.73 10.28 
AS 178 0.57 0.32 1.12 24.90 7.35 
FL Wf 4.91 3.69 6.56 21.30 -l 
FW 7 3.40 2.56 4.40 17.89 = 
Table 31 Differences in apertural spacing in longitudinal rows in 
Goniocladia cellulifera (in mm). 
Carinal ridge -------------------------------------------- >Median keel 
(barren surface) (obverse surface) 
1 2 3 4 5 6 7 
NM 13 13 13 12 12 10 5 
Mn 0.73 0.52 0.43 0.42 0.39 0.33 0.47 
Mx 1.12 1.04 1.00 1.02 1.00 0.73 0.75 
X 0.86 0.71 0.64 0.61 0.59 0.55 0.53 
DISCUSSION. Goniocladia cellulifera is quite common in the Lower 
Carboniferous of the British Isles, where it has been described from 
the Midland Valley of Scotland, Cumbria, Northumberland, and 
Yorkshire. It is very distinct with an unusual laterally flattened 
branch bearing a number of rows of autozooecial apertures and a 
sharp median ridge. 
It was first described as Carinella cellulifera by Etheridge (1873a), 
but he later realised that that generic name was pre-occupied by a 
nemertean worm, and so proposed the name Goniocladia (Etheridge 
1876). He suggested (Etheridge 1873a, 1873b), on the evidence of 
external features, that Goniocladia was an intermediate between 
Polypora M‘Coy and Fenestella Lonsdale. While Goniocladia does 
possess a median keel (as in Fenestella) and has more than two rows 
of autozooecial apertures (as in Polypora), internally it resembles 
neither. In Goniocladia the zoarium is divided into two by a straight 
