20 PEOF. P. MAETrN" DTJIfOAjr's BETISION OP THE 



G-enus Conoctathtjs, d'Orligny, 1849. 



The corallum is free, conical, trochoid, straight, the costse are 

 sublamellar, the septa are exsert and strongly echinulate on the 

 sides. The columella is absent ; and there are pali before the 

 penultimate cycle of septa. 



Distribution. — Fossil. Miocene of Mayence ; Cainozoic, Aus- 

 tralia. — Becent. South-Australian and New-Zealand seas. 



Genus Bisttlia, Tennison Woods, Trans. Phil. Soc. Adelaide, 

 8. Australia, 1877-78, p. 114. 



Corallum simple, conico-cylindrical, attached. Columella a 

 double style. 



Distribution. — Fossil. Tertiary deposits of Australia. 



There is much difl&culty in placing the next genus ; and 

 indeed it would be insuperable were it not for the admirable 

 drawing of one of the species. The description of the genus 

 TrematotrocTius by Tennison Woods is very short ; but the light 

 thrown on it by the illustration is very, but not perfectly, 

 explanatory. 



Mr. Tennison Woods differentiates as follows : — 



Genus Teematoteochus, T. Woods, Froc. Foyal Soc. New South 

 Wales, vol. xii. 1878, p. 59, fig. 2. 



" Corallum free ; visceral chambers free. Septa distinct, only 

 united in the middle. Pali exsert. No endotheca or synapticula. 

 Wall perforated." 



The figure and the description of the species indicate that 

 the septa are stout, not perforate, and that the perforations are 

 perfectly symmetrical, and in the intercostal spaces only. The 

 " pali " are not more than paliform lobes or dentations around 

 the circular axial space which is bounded by the united inner (not 

 middle) ends of the septa. The appearance is that of a species 

 of Turbinolia or Gonocyathus, with the costse not so projecting 

 as is usual. The intercostal dimples of the Turbinolice of the 

 Eocene of Bracklesham do not perforate ; and they are on either 

 side of a line running down the intercostal spaces ; but the 

 wall is very thin, and often wears away during fossUization. 

 The arrangement of the septa in Trematotrochus is, however, 

 different from that of any species of Turbinolia. 



