101 



septa of the sarae and higher cycles below the first. The septa 

 of the fourth cycle unite with those of the third some way before 

 the latter reach the columella. 



Pali are present, in three crowns, opposite the first three cycles 

 of septa, and in those half-systems in which a sixth cycle of 

 septa is partially developed there are also pali opposite the fourth 

 cycle. The pali of the iunermost crown are the srnallest, and 

 those of the outerniost crown are the largest. 



There is an abundant fasciculate or radiculate columella, with 

 which the first three cycles of septa unite. 



Major diameter of calicle 43 millim. 



Minor » » » 34 » 



Greatest height, to summit of the exsert primary septa 28 » 

 Least height, in interval between two primary septa 18 » 

 Length of rootlets over 20 » 



This species is evidently very closely related to Stephanotrochus 

 Tatei Dennant, from the South Australian Tertiaries (Trans. Roy. 

 Soc. S. Australia XXIII. 1898-99, p. 117, PI. III. Figs. la—c). 



17. Stephanotrochus xoeberianus n. sp. 



Corallum bowl-shaped, with a strong bulge and thickening 

 where the sidewall joins the base. 



The base, which is covered with a dull epitheca, has a central 

 wart-like scar from which costas radiate, the costae of the first 

 two cycles being distinct but not prominent ridges while those 

 of the lower cycles are fine strige. 



On the sidewall the costae, which are all granular and of equal 

 size, gradually become more and more distinct as they approach 

 the calicular margin. 



The calicular fossa is circular, deep, and capacious. 



The septa appear to be regular, but are, in fact, very irregular 

 owing to the occasional absence from some of the half-systems 

 of those of the fifth cycle. The primaries and secondaries (twelve 

 in number) are large and conspicuously exsert above all the others ; 



