204 Dr. G. J. Hinde — Western Australian Fossils. 



EXPLANATION OF PLATES VIII. and VIIIa. 

 PLATE VIII. 



Fig. 1. — Cyathophyllum virgatum, sp.n. ; la, a fragmentary specimen, natural size; 



lb, transverse section enlarged two diameters. 

 ,, 2. — Cyathophyllum depression, sp.n. ; la, the upper surface, showing the 



weathered summits of the corallites ; 2b, a transverse section, enlarged. 

 ,, 3. — Pachypora tumida, sp.n., natural size. 

 ,, 4. — Syringopora reticulata, var. patula. Portion of a specimen, showing the 



corallites in section. Natural size. 

 ,, 5. — Aulopora repens, Knorr and "Walch. 

 ,, 6. — Hexagonella dendroidea, Hudleston, sp. A section showing the thickness of 



the branch. 

 ,, 7. — Stromatoporella Eifeliensis, Nicholson; la, lb, specimens natural size; 



1c, vertical section enlarged. 

 ,, 8. — Actinostroma clathratum, Nicholson; 8a, vertical section natural size; 



8b, portion of the same enlarged. 



PLATE VIIIa. 

 Figs. 1-1/. — Plerophyllum australe, Hinde. 

 ,, la, lb, lc. — Three imperfect examples natural size; lb shows the exterior 



surface in its natural condition ; in 1« and lc the surface has been weathered, 



and the median lamina? of the septa are exposed. 

 ,, _ Id. — A transverse section of the calice, with the small cardinal septum 



inclosed between two larger septa above. Enlarged 2jt diameters. 

 >, le. — A transverse section of another specimen, similarly enlarged, in which 



the smaller septa are proportionately more developed, and the small septum 



between the two larger is lateral in position, 

 j, 1/. — Another transverse section, similarly enlarged, in which one portion has 



been completely infilled by stereoplasm. 

 ,, 2, 2a. — Plerophyllum sulcatum, Hinde. 

 >, 2. — An imperfect specimen, showing renewals of growth and the longitudinal 



rugae of the surface. 

 ,, 2a. — A transverse section of the same, enlarged 2\ diameters, showing com- 

 plete solidification by stereoplasm. 

 ,, 3, 3a. — Polypora aitstralis, Hinde. 



„ 3. — A fragmentary specimen showing the celluliferous surface, natural size. 

 ,, _ 3a.— A portion of the same, enlarged 5 diameters, showing the form and 



disposition of the fenestrules and cell -apertures. 

 ,, 4, 4a. — Shombopora tenuis, Hinde. 

 j ) 4. — A portion of the surface showing the cell- apertures and the interstitial tubes 



and spines. Enlarged 20 diameters. 

 ,, 4«. — A portion of a longitudinal section, showing the disposition of the cells 



and the thickening of the walls near the surface. 

 ,, 5 — bd. — Hexagonella dendroidea, Hudleston, sp. 

 „ 5. — An imperfect stem or branch, showing the mode of growth, the linear 



ridges, the maculae, and the cells of the exterior surface. Natural size. 

 ,, 5a. — A portion of a transverse section of a branch, showing (in section) the 



median layer and the cells ( =autopores) on it. Enlarged 20 diameters. 

 ,, 5b. — A portion of a median longitudinajAsection of a branch, showing the 



recumbent position of the cells on the median layer in their first stage of growth, 



their subsequent vertical direction, the tabulae traversing them at intervals, and 



the vesicular interstitial tissue of the central area. Enlarged 20 diameters. 

 ,, be. — A portion of the surface of Fig. 5, enlarged 20 diameters, showing the 



oblique projection of the lips of the cells, the manner in which they are partially 



or entirely closed by calcareous lids, the tuberculate character of the interstitial 



areas, and the raised ridges. 

 ,, bd. — A portion of a tangential section, showing the cells with distinct walls, 



and the cloudy appearance of the solid interstitial substance of the outer zone of 



the branch. Enlarged 20 diameters. 



