220 F. Chapman: 



ticulate posterior maa-gin of the articulamentum of the tail valve, 

 and the slightly greater elevation of the dorsal area in the former. 



Locality and Horizon. — Balcombe's Bay, Port Phillip. Ter- 

 tiary (Baloombian). Collected by Mr. W. Kershaw. 



For valuable assistance in comparing these fossils with fhe 

 living types. I am much indebted to Mr. R. A. Bastow. 



EXPLANATION OF PLATES. 



Platk XVIT. 



Fig. L — Spicules of Ecionema newheryi, McCoy sp. An oxea ; 

 slightly curved form (the principal skeletal spicules). 

 Fig. 2. — An oxea, having a sigmoidal curve. 

 Fig. 3. — Protriaene, with straight oladi. 

 Fig. 4. — Protriaene with curved cladi. 

 Fig. 5. — Dichotriaene. 

 Fig. 6. — Another, fragmentary specimen. 

 Fig. 7. — Microrabd (microstrongyle), showing pitted surface. 

 Fig. 8. — Probably a spiraster, with spines developed towards one 



end. 

 Fig. 9. — Microxea, with whorls of spines. 

 Fig. 10. — Spheraster, with arms terminated by spines. 

 Fig. IL — Sterraster. 

 Fig. 12. — Sanidaster. 



Fig. 13. — Protriaene, with sigmoidally curved cladi. 

 All figures on the above plate magnified 52 diameters. 



Plate XVIIL 



Fig. 1. — Comoseris (Oroseris) australis, sp. nov. A drawing from 

 a wax squeeze. x 2. 



{""ig. 2. — The same. A calice more highly magnified, x 4. 



Fig. 3. — Cliona mammillata, sp. nov. Natural casts of the cham- 

 bers. X 2. 



Fig. 4.- — ? Cliona peregrinator, sp. nov. A natural cast, x 2. 



Fig. 5. — Ischnochiton (Ischnoplax) granulosus, Ashby and Torr. 

 sp. Posterior valve, dorsal view, x 3. 



Fig. 6.- -The same ; side view. x 3. 



