260 



Costae simootli : on the fiat surfaces they converge from, 

 the calice downwards to the projection at the base, while on the 

 edges they ar» doubly curved, first inwards and then outwards ; 

 the central costae are almost uniform in size throughout, but 

 those flanking the edges become very broad at their basal ter- 

 minations. Of the more central costae a few only reach the 

 base and are joined at varying heights on the wall by the rest; 

 those adjoining the edges are free. A faint shining epitheca is- 

 sometimes present, especially in young examples. 



Height of corallum, 5.5 mm. ; diameters of calice, 4 mm. 

 and 2 mm. 



Locality, ct-c. — Eocene, Muddy Creek. Collected from a re- 

 made bed (junction of Eocene and Miocene) at Forsyth's, 

 Grange Burn, by Mr. T. S. Hall, and by myself in the lower 

 beds. Rare. 



Conocyatlius serobiculatus, -^iicc. nor. 



PI. vi., figs, la, h. 



Corallum small and conical, with rounded, costulate base. 

 Calice circular. Septa laterally Sjpined, and in six systems- 

 with three cycles. They vary in length according to order, the 

 primaries being longest. The tertiaries are slighter than the 

 other two orders, which are subequal in size. There is no 

 columella, but six elongate and prominent pali surround the 

 central axial space, and are placed before the secondary septa. 



There are four complete cycles of costae, of which only the 

 first three have septa corresponding to them. Those of the 

 fourth cycle are very thin, but well marked at the calicular 

 margin as delicate projections from the wall in the spaces 

 between the other costse ; they reach only from a quarter to- 

 a third from the margin. The three lower orders are less 

 slender than the fourth, and after passing these they enlarge 

 to twice their former size. The tertiaries again cease abruptly 

 near the base, to which only the twelve primaries and second- 

 aries extend, and after passing the tertiaries they in tura 

 become still stouter than before. All the costae are smooth and 

 free, there being no union of orders on the wall. In most 

 specimens there is a regular series of punctations or pores in 

 each intercostal space, but in a few young individuals these 

 are replaced by minute dimples or fossettes. Apparently, 



therefore, the wall wears gradually away where it is thinnest,, 

 perhaps during fossilization, and the result is that the inter- 

 costal spaces become fenestrated. 



Heio-ht of corallum, 5 mm. ; diameter of calice, 2.5 mm. 



