[Proc. Rot. Soc. Victoria, 29 (N.S)., Pt. I., 1916]. 



Akt. V. — New or Little-known Victorian Fossils in the 

 National Museum. 



Part XIX. — The Yeringian Gasteropod Fauna. 



By FREDERICK CHAPMAN, A.L.S., &c. 

 (Palaeontologist to the National Museum, Melbourne). 



(With Plates II.-VI.). 



[Read 13th July, 1916]. 



Introductory. 



Of late years a considerable number of Silurian gasteropods have 

 been added to the collection of the Melbourne National Museum, 

 chiefly through the assiduous work of collectors whose names are 

 mentioned in the body of the text, and who have permitted the 

 Museum to benefit by their discoveries. Amongst the more notable 

 genera of Silurian gasteropods herein described are : — HelcionojJsis. 

 I'emnodiscus, Carinaropsis, Cyrtostropha, Crospedostonw, Orthony- 

 chia, Diaphorostoma and Eercynella, all of which appear to be new 

 to the Southern Hemisphere. 



Coelocanlus is here used to replace Niso (Vetotuba); the murchi- 

 sonian affinities of the Cave Hill specimens being clearly shown in 

 the Museum examples. The wide area of distribution for this 

 genus in palaeozoic times is thereby extended into the Australian 

 region. A new genus, Liomjjhalus, is herein suggested for smooth 

 euomphalid shells with biconcave surfaces and partially open whorls. 



A noteworthy feature of the Yeringian fauna is the comparative 

 abundance of gasteropoda in contrast with their rarity in the 

 Melbournian. The complete list of Yeringian gasteropods comprises 

 36 species, whilst there are only six species known up to the present 

 time in the Melbournian. This gives a deeper Avater aspect to the 

 Yeringian sea as a whole, and is concomitant with the data derived 

 from the lithological structure and general stratigraphy of the two 

 groups of beds in question. 



So large a proportion of the Victorian Yeringian gasteropods is 

 here described for the first time, comprising sixteen new species, and 

 a variety, that it seemed advisable to make this paper a complete 

 record of all the Yeringian species, so far as the material is 

 sufficiently well preserved for descriptive purposes- 



