tHB AVONIAN OF THE AVON OOROE 
147 
Lonsdalia, 
Corallum always compound and either dendroid or massive. 
Central area circular and reticulate ; mesial plate short and 
entirely included within the area ; lamellae frequently very 
numerous and purely radial, crossed by concentric tabular 
intersections. 
Septa not numerous, thickened in the middle, and seldom 
reaching the outer wall ; intermediates present or absent. 
The external area is only represented by the dense ring of 
vesicles which forms the inner wall. 
The peripheral area is usually very broad and built up 
entirely of large vesicles. (It is within this area that the 
young corallites separate out.) 
Figures : Ed. and H. Plate 43 
[N.B . — Axofhyllum may be regarded as a Lonsdalia in which 
the whole of the central area forms a solid rod, for a horizontal 
section of the solid central columella in this genus exhibits the 
characteristic 7io?^5(^a^^^^-structure. The external area is, how- 
ever, of an Acrophyllum-tj^Q.'] 
Carcinofhyllum, 
