the Genus Stenopora, Lonsdale. 179 



of the corallum, the corallites in this region being angular 

 and exhibiting the primordial wall distinctly. Another cha- 

 racteristic feature is that the annular thickenings of the walls 

 of the corallites in the peripheral region of the corallum are 

 nearly continuous with one another (PI. III. figs. 10 and 11), 

 and are not separated by marked unthickened segments. 

 Tabula3, further^ are very sparsely developed, and are often not 

 recognizable at all. The mouths of the tubes, however, are 

 sometimes partially closed by perforated diaphragms (PI. III. 

 figs. 11 and 12). These structures, as previously noted, 

 can hardly be anything else than jierforated tabula3, produced 

 at the final period of growth, and they have been well figured 

 by Lonsdale (Phys. Descript. N. S. Wales, pi. viii. fig. 2 h). 

 In longitudinal sections of the thickened peripheral region of 

 the corallum the acanthopores are seen as conspicuous narrow 

 tubes (PL III. figs. 10 and 11) running in the thickness of 

 the walls. 



Locality and Formation. The original specimen of Steno- 

 pora tasmaniensis, Lonsd., appears to have been lost, as is 

 also the case with the Strzeleckian type of the species. The 

 British Museum, however, contains several specimens which 

 more or less clearly belong to this form, viz : — (1) A number 

 of dendroid examples in a greenish ashy-looking matrix from 

 Harper's Hill, near Maitland, New South Wales. One of 

 these specimens shows mural pores excellently. Thin sec- 

 tions of one of these specimens are here figured (PI. IH. 

 figs. 9-11). (2) Two examples from Port Lowell, Tasmania, 

 in a light shelly limestone. (3) A remarkable frondescent 

 specimen, numbered 48,746, also from Tasmania. In this 

 example the corallum is only 3 millim. in thickness, and con- 

 sists of two layers of corallites springing from a median 

 plane (PI. III. fig. 12). (4) Two examples in a dark- 

 coloured matrix, from Killyraoon, near Fingal, Tasmania. 

 (5) A large cylindrical branched stem, likewise from Tas- 

 mania, and resembling the figured Strzeleckian type in 

 general aspect. In minute structure, however, the tubes of 

 the peripheral region show annular thickenings separated by 

 distinct unthickened segments, thus giving rise to correspond- 

 ing appearances in the tangential section ; and we are there- 

 fore not clear as to the identity of this specimen with *S'. 

 tasmaniensis. 



Stenopora Leichhardtii^ n. sp. (PI. III. figs. 7 and 8.) 



Spec. char. Corallum dendroid, of cylindrical branching 

 stems, which vary in diameter from less than a centimetre up 

 to H centim. The corallites in the centre of the branches 



