Victorian Fossils. 217 



Characters of the corallum. — There is little to add to the tech- 

 nical description given by Mr. W. S. Dun, and later, by the writer, 

 ■excepting to say that the corallum attains much larger dimensions 

 than was then stated, a specimen before me, from the junction of 

 the Woori Yallock and Yarra, indicating at least 3 corallites 

 when complete. 



The basal epitheca is perhaps more strongly concentrically 

 wrinkled than in the other recorded species, and seems to have 

 been also covered with a fine pustulation. 



Intermural gemmation is shown by the intercalation of tri- 

 angular corallites between the normal quadrangular corallites. 

 The outline of the corallites in P. megastomum are either pen- 

 tagonal or quadrangular (trapezoidal in shape), or broadly tri- 

 angular when interpolated between other normal corallites. On 

 the other hand the foreign species have mostly elongate rhomboid 

 • corallites as typically shown in P. problematicum, Goldfuss 10 ; 

 irregularly polygonal in P. stylophora, Eaton sp. 11 ; and hexagonal 

 in P. amazonicum, Katzer 12 . 



It seems impossible to separate the other so-called species, 

 P. lonsdalei, Richter 13 , found in Devonian strata in Thuringia, 

 which seems to show a wider spacing of the peripheral corallites 

 than usual, but which are of the typical form seen in P. problem- 

 <aticum. 



There is one species, however, which does seem to simulate 

 the Victorian form to some extent, viz., P. Constantino politanum, 

 Roemer 14 , in the breadth and general shape of the corallites. This 

 was obtained from the Devonian of the neighbourhood of Con- 

 stantinople. 



Like other representatives of the genus this tabulate coral is 

 in the Victorian specimens only preserved as casts, in mudstone 

 or sandstone. They differ from other species in the larger size 

 -of the corallites with more quadrate form and in being generally 

 arranged in fewer cycles. In one mudstone cast, from loc. B. 23, 

 the tabulae are fortunately shown as thin irregular plates, some- 



10. Petrifacta Germaniae, vol. I., 1826, p. 113, pi. XXXVIII., fig. 18; 

 vol. II., p. 286, pi. CLX., fig. 19. Also G. and F. Sandberger, Verst. Rhein. 

 Schicht. Nassau, 1850-6, p. 405, pi. XXXVII., figs. 8, Sa-c. 



11. Astraea stylophora, Eaton, Geol. Text-book, 1832. Pleurodictyum 

 .stylophorum, Eaton sp., Nicholson, 1879, Pal. Tab. Corals, p. 143, pi. VIII., 



figs. 1, la, b, text-fig. 22. 



12. Geol. unt. Amazonasgebietes, Leipzig, 1903, p. 192, pi. IX., figs. la-c. 



13. Zeitschr. d. deutsch, Geol. Gesellsch, vol. VII., 1855, pp. 562, 563, 

 :leKt-fig. 5. 



14. Neues Jahrb., 1863, p. 519, pi. V. 



