PROM THE TERTIARY DEPOSITS OP TASMANIA. 343 



tures of the coralluni, the great development of the exotheca, the 

 long filiform continuations of the greater costse which connect the 

 corallites, and their occasional absence, and also for the small 

 columella and indefinite septal number. The presence of corallites 

 with the quaternary arrangement is very suggestive. 



Alliances. The species is eminently Solenastrasan in its aspect ; 

 and were it not for the costal development, it would be associated 

 with that genus. In some parts of the corallum the distinction 

 between the structures and peculiarities of the genera Heliastrcea 

 and Solenastrcea are by no means decided ; but in others the long 

 wavy costas mix in and amongst the exotheca, and unite with those 

 of the neighbouring calices. The alliances of this Heliastrsean 

 must be sought amongst those with long costoe, much exotheca, a fair 

 amount of endotheca, and a small columella. Species thus distin- 

 guished are not found amongst the recent reef-building coral faunas. 

 The nearest allies of the new species have been found in the same 

 strata as the congeners of the Australian Placotroclii, namely in the 

 Miocene of the West Indies ; but in estimating the value of this 

 remote connexion, it must be remembered that there is hardly any 

 palu3ontological evidence relating to the Tertiary reef-corals of the 

 Pacific area. 



The species differs much from the Heliastrcea I described from 

 the Tertiarica of Java *. 



Heliastrcea immersa, Reuss. f , from the older Tertiaries of Monte 

 Grumi, near Castelgombcrto, is of the same general type as the new 

 form, as it has distant corallites, a peculiar septal number, long 

 wavy costae, and apparently a thin wall and a small columella. 



The new species, when compared with the Heliastraeans of the 

 Ootatoor group of the Cretaceous formation of Southern India, pre- 

 sents remarkable affinities with Heliastrcea cortica, Stol. $ ; for this 

 interesting Indian reef-coral has all the characters of the Tas- 

 inanian form, but differs in possessing thick costse, those of the 

 small intermediate septa being large. Even the other species from 

 these Indian rocks (Heliastrcea rotunda, Stol.) is not without its 

 resemblance to the Tasmanian species. 



Thamnastr^ea sera, sp. nov. Plate XXII. figs. 4-6. 



The corallum is solid and short, being about T 6 F inch in height ; 

 and the base is incrusting ; the upper surface is subplane ; and the 

 corallites are distant and widely apart. The calices are slightly 

 depressed below the level of the long and numerous costse; their 

 fossula is small and shallow ; and the columella is papillary, being 

 formed by oblique and rounded processes from the free ends of the 

 septa. The septa are continuous with the costse, and are at the mar- 

 gin of the fossula about twenty-six in number ; they are subequal, 



* Quart. Journ. Geol. Soc. vol. xx. 1864, p. 72. 



t Eeuss. Pal. Stud, liber die alt. Tertiar. der Alpen, 1868, 1. Abtheil. 

 p. 30. 



I Stoliczka, Palasontol. Indica, vol. 14, 4 ser. pi. viii. f. 4-=-8 ; The Corals or An- 

 thozoa, Mem. Geol. Survey of India, 1873. 



