CARBONIFEROUS CORALS AND BRACHIOPODS 103 
the plane of section with the fossular depressions of higher 
tabulae. 
In the horizontal section of a Campophyllum, the bilateral 
symmetry is not conspicuous, but, as in a Cyaihophtjllum, 
is more or less marked out by the presence of one or more 
shorter septa at some point of the septal ring ; the longer 
septa, however, on either side of the shorter ones, are 
straight and of normal pattern, and there is no indication 
of a depression in the floor of the tabula at this point. 
Caninia cylindrica, var. bristoliensis. PI. I., Fig. 4. 
Corallum cylindrical, seldom exceeding 4 cm. in dia- 
meter. 
Vertical section : central area occupied by broad, hori- 
zontal tabulae which are well spaced vertically ; an outer 
zone of coarse, ascending vesicles, extremely variable in 
width and often partially absent. 
Horizontal section : Septa 50 to 54, thick (bilaminar) 
and lanceolate, forming a strongly marked septal ring ; 
the septa are frequently continued across the tabulae as 
thin flexuous striae, which exhibit the Zaphrentis type of 
grouping. 
The fossula is elongate and conspicuous and contains a 
unique, shorter septum enclosed in one or more arches, 
as explained above. Betv/een the septa the vesicles are 
fev/ and inconspicuous. 
Outside the septal ring is a zone of fine vesicular tissue, 
very variable in width at different points ; this outer 
vesicular ring is crossed by very thin prolongations of the 
septa and by a second series of equally thin intermediates. 
The innermost limit of this zone is formed by a strongly 
thickened inner wall, which runs, as a connected series of 
discontinuous arcs, from septum to septum, each short arc 
connecting the thick ends of two adjacent septa ; at the 
fossula, the inner wall exhibits a strong outward projection. 
