210 



ithe others near tlie base. In the young example just men- 

 tioned the junction of the higher orders with the principal is 

 nearer the calice, and from a third to two-thirds from its 

 margin. The wall is slender, and the costae, like the septa, 

 extend outwards from it. 



The dimensions of the type, which is evidently an adult 

 example, are: — Height of corallum, 9 mm.; length of calice, 

 10 mm. ; breadth of calice, 9 mm. The calice figured is 7 

 mm. long and 6 mm. broad. Its corallum is well presei^ved, 

 and is 6.5 mm. high. 



Locality, cCt. — In Eocene strata at Brown's Creek. Two- 

 whole examples, aind a portion of a third ha\^e only been found. 



Troehoeyathus planicostatus, -^pec. nov. PJ. i., figs. 3a, h. 



Tlie corallum is longer than broad and pyramidal shaped 

 with a shariply pointed base. The calice is subplane ajid 

 elliptical, the major and minor axes being in the ratio of 100 

 to 70. 



The septa are exsert and in six systems with three cyclesi. 

 They are spined on the lateral edges, while lower down there 

 are small granules. All are short, but the primaries; are 

 longer than the secondaries, and these again than the ter- 

 tiaries. The two first orders are stout and subequal, and thei 

 tertiaries slender. 



The axial space is large, aaid in the centre there is a fas- 

 cicular columella having three longitudinally arranged lobes 

 on its surface. Well marked, spined pali are placed in two 

 crowns before the primary and secondary septa., and are con- 

 nected with these and also with the columella by short, stout, 

 sunken processes. 



The costse in this coral form its most remarkable feature. 

 They are of two kinds; first, 24 prominent, equal, flat, and 

 almost plain costiEe, very broad but rounded off at the top, 

 and then regularly diminishing tO' the pointed base. They 

 reach to the margin of the w^all only, and are quite distinct 

 from the seipta, the exsert portions of which present the 

 appear aaice of being inserted in each interspace. Tlie second 

 series of costae, also 24 in number, are continuations of the 

 three orders of septa, but below the exsert portions of these, 

 that is, from the margin downwards, they are represented 

 on the wall by extremely thin, granular, and sunken lines, 

 which can usually be traced almost to the base. In a young 

 fresh looking specimen in my collection, the contrast between 

 the plain, prominent costse, terminating at the margin of the 

 w^all, and the adjacent spined. exsert septa rising much above it 

 is very striking. The example selected as type is much larger, 

 but, though in good condition, it is not quite as well preserved. 



