130 
THE AVONIAN OP THE AVON OOROB 
IV. Notes on the Genera of Carboniferous Corals and 
Brachiopods. 
These notes are designed for the use of students who have 
already a general acquaintance with the structure of fossil corals 
and brachiopods, but who are unacquainted with the generic 
distinctions which have been made in recent years. 
Only those characters are described which can be readily 
observed in the specimens and cross-sections with which the 
field-geologist has usually to deal. 
CORAL GENERA. 
Note. — The only readily- accessible work of reference, in which Carbon- 
iferous corals are figured, is the ‘ Monograph of British Fossil Corals ’ by 
Edwards and Haime (Pal. Soc. 1852). Reference is here made to this work 
(under the abbreviation Ed. and H.) in all cases where a genus is adequately 
illustrated in it. In other cases, a diagrammatic figure has been introduced 
into the text. 
Syringo'pora. 
Corallum compound. 
Corallites : narrow, flexed, cylindrical tubes connected by 
hollow tubular connectors. 
Septa : longitudinal rows of spines. 
Tabulse : funnel-shaped sheets which are attached to the 
thick wall and hang downward into the cavity of the tube. 
A horizontal section cuts the corallites in circular 
or oval rings which are connected by cross tubes wherever the 
section happens to have cut through a connector. Inside the 
wall of each corallite, there are usually one or more thin con- 
centric rings which result from the intersection of the plane 
of section with the internal tabulae. 
A vertical section shows the longitudinal tubes 
connected by a series of cross tubes ; the tabulae are seen as 
a series of funnels, very irregular in shape, which hang down, 
one inside the other. 
