100 



Denuropora — Coenenchyma smooth, calices scattered. 



Trachypora — Coenenchyma vermiculate. 



Rhabdopora — Coenenchyma finely hispid, ealices serial, septa 



very distinct. 

 Sertatopora — Septa scarcely visihle. 



The genus Seriatopora is thus defined — Corallum aborescent ; 

 coenenchyma finely hispid ; ealices disposed in an ascending 

 series ; columella large, compact, and placed in the direction of 

 the axis of the branches ; visceral chambers obliterated com- 

 pletely in the course of growth. 



It is doubtful whether there are ten species in all of this 

 genus, but it is one of the most common on all the barrier reefs 

 of Australia ; and probably Seriatopora subulata, is the most 

 extensively distributed throughout the Pacific and Australian 

 seas. There are no fossil forms known to me, unless those 

 which may occur in the raised beaches on the coast of Java. 

 The discovery of the present fossil (herein described as Seria- 

 topora cmbiqua) in the Australian Tertiaries is a fact of great 

 interest, especially as it has been found in a latitude far out- 

 side where any reef -building corals exist now. 



Seriatopora antiqua, spec. nov. 



The fragment is evidently a portion of a broad, compressed, 

 and coalescent branch, resulting from the union of smaller 

 ones, as in S. subulata. The branches are hollow. The coenen- 

 chyma is very hard and compact, and shows no traces of struc- 

 ture where broken ; it is much worn, but here and there 

 exhibits traces of its hispid character in uumerous worn 

 granules. Calices about one millimetre in diameter, very 

 close, surrounded by a raised ring, rather deep. Columella of 

 the form of a large rounded tubercle, much higher than the 

 septa, which are six in number, visible, but not conspicuously 

 so. 



The fragment is 25 millimetres long, ten thick, and fifteen 

 wide ; but there are also projections like the terminations of 

 branches. 



In the size of the calices and the distinctness of the septa, 

 the species resembles Seriatopora spinosa, Ehrenberg, which is 

 found in the Red Sea. 



Plesiastrsea grandis, -^ec. nov. 

 Corallum a much-worn fragment, about 65 millimetres high, 

 75 wide, and from 20 to 25 thick. The fragment is broken, so 

 as to expose the plan of the calices and every kind of section. 

 Corallites evidently radiating in a convex manner from a 

 central disc • they are long, closely packed, and united by a 



