THE AVONIAN OF THE AVON GORGE 
139 
(4) An outer area in which vesicles are strongly developed^ 
but in which radial structure is inconspicuous. 
This genus is unsatisfactory on two counts : — 
(a) It includes corals with very distinct types of structure. 
(h) In the Ganinoid section, certain species possess a distinct 
but shallow fossula and their reference to CamfOfhyl- 
lum, rather than to Caninia, is the result of a careful 
comparison of all their characters with typical examples 
of both genera. 
Two sections of this genus are markedly distinct : — 
I. The Ganinoid section, characterized by a well- 
marked inner wall and a purely vesicular outer area. (A series 
of septal teeth project from the outer wall into the vesicular 
area.) 
Of this section there are two subsections ; — 
(a) A group in which the septa are long, thick and tapering 
and very closely approximated. 
(h) A group in which the septa are short, thin, and broadly 
spaced (CamfO'phyllum aff. Murchisoni, Vaughan 
belongs here). 
II. The Glisiophylloid section, characterized by 
its broad vesicular area which is distinctly and regularly 
radiated by thin prolongations of both series of septa. The 
interspaces between these prolongations are filled in with 
close-set vesicles which are more closely approximated at the 
inner boundary of the area, and consequently mark out a 
conspicuous inner wall. 
In this section, the vesicular area is identical in structure 
with that of the external area in the Glisiophyllid group. 
{Campophyllum derbiense, Vaughan [M.S.] is a typical 
representative of this section.) 
[The type figure of Campophyllum Murchisoni, Ed. and H. 
(Plate 36, Figs. 2, 2a, 3,) probably represents a species belonging 
to this section, but, if so, the inner wall is incorrectly 
drawn.] 
