164 Dr. P. M. Duncan on Fossil Corals and Echinoderms 



6, Placotrochus deltoideus, n. sp. PI. V. fig. 5. 



The coral is conical, finely pedicellate, greatly compressed 

 inferiorly, less so superiorly, has a rugged, sharp, not very pro- 

 minent costal projection on either side, but is not spined. The 

 calice is large, elliptical, with rather acute ends ; apparently, the 

 smaller axis is higher than the longer ; its wall is thin, and the 

 fossa is shallow, except centrally, where it is deeper and presents 

 the thin lamellar columella. The septa are numerous, unequal, 

 the larger touching the columella and joining it by small pro- 

 cesses, the smaller reaching but a little distance inwards. There 

 are six systems and five incomplete cycles. The septa are not 

 exsert, are feebly arched, and are very delicate ; the laminae are 

 granular, and their internal margin is often wavy. The colu- 

 mella is very sharp, thin, faintly papillate, and distinct. The 

 costse are small, except the lateral crests. The epitheca is 

 strongly developed, being in arched ridges. The costse are often 

 chevroned beneath it. The lateral crests form an angle of 60°. 



Height of coral 1 inch ; length of calice -^ inch, breadth of 

 calice -j^ inch. 



Locality. Muddy Creek, South Australia. 



Variety : Bursarius, with the lateral crests forming convex 

 ridges inferiorly. 



7. Balanophyllia Australiensis, u. sp. PI. VI. fig. 1. 



The corallum is pedicillate, free, long, cylindrical, tapering 

 and occasionally curved. The calice is elliptical, the fossa is 

 shallow, the septa are not exsert, and the columella is large. 

 There are five cycles of septa in six systems, the smaller septa 

 joining others very close to the wall of the calice, which is thin. 

 The costse are numerous, equal, and consist of fine laminae, each 

 of which has two rows of delicate dentations connected trans- 

 versely. The epitheca is seen near the base. 



Height of coral 1 1 inch ; width of calice -^ inch. 



Locality. Muddy Creek, South Australia. 



8. Trochoseris Woodsi, n, sp. PI. VI. fig. 2. 



The coral is fixed by a small pedicel, above which it expands 

 at first irregularly, and then largely. The wall is covered by a 

 pellicular epitheca, which shows traces of subequal costae. The 

 calice is widely open, irregularly circular, with a thin edge and 

 a small central fossula. The septa are not exsert, are crowded 

 and delicate, there being not much difi'erence in the size of those 

 of the principal cycles ; in six systems of five cycles, with half 

 a sixth in each. The smaller septa very generally join the 

 larger, and the larger reach the central fossula. The laminae 



