Introduction. 



From his journey in Australia Dr. Mj Öberg brought horne some stony corals, the 

 determination of which was kindly cntrusted to me by Dr. Mjöberg. 



The collection is very valuable for our knowledge of the corals from the west coast 

 of Australia, a district from which but little has been recorded. It contains 20 species 

 of which 4 have not been previously described in the literature of the subject, and have 

 therefore been established as new species; one new genus has been created. 



In order to show the differences in the arrangement of the septa in the genus Po- 

 lyphyllia, a part of a specimen of P. novae-hiberniae (Lesson 1833) has been figured, 

 though no specimen of that species was collected by Dr. Mjöberg. 



In connection with the discussion of the species of Heterocyathus, H. alternatus 

 has been described and figured. That species was created by Verrill in 1864 and noticed 

 by him from Gaspar Straits, but it did not attract any attention until 1911, when 

 Harrisox found reason to consider it identical with Gardiner's Type II of Heterocya- 

 thus aequicostatus E. k H. As I can not share that opinion, and as the description of H. 

 alternatus V. is somewhat incomplete, and the figure published by Verrill is not suffi- 

 ciently distinct, I have redescribed it below, though there are no specimens of that 

 species in Dr. Mjöberg's collection. 



I am much indebted to Professor Théel, Keeper of Zoology to the Swedish State 

 Museum, who placed the collections of corals in the Museum at my disposal, and I take 

 the opportunity to exr^ress my best thanks to Dr. N. Odhner for much valuable advice. 



