[Proc. Rot. Soc. Victoria, 26 (N.S.), Pt. I., 1913]. 



A HI'. IX. — New or Llttle-knoivn Victorian Fossils in the 

 National Mtiseam. 



Pakt XVI. — 80MK SiLUKiAN Braciiiopoda. 



By FREDEIUCK CHAPMAN, A.L.S., F.ll.M.S. 



(Palaeontolof^ist to the Museum). 



(With Plates X. and XI). 

 [Read 12th June, 1913]. 



Introduction. 



The fauna of the Victorian Silurian strata includes a rich assem- 

 blage of brachiopods; and although the number in this group, 

 together with the present contribution, now amounts to about 60 

 species, yet probably not more than half has been described. 



A selection of the better preserved specimens has been studied, 

 .and the results, given herewith, help to show how interesting is the 

 Australian Silurian fauna compared with that of other widely 

 separated areas. One feature of the present series is the marked 

 Devonic element found in the otherwise Wenlockian or newer 

 .Silurian facies of our Yeringian mudstones. 



Amongst the more noticeable points brought out by the present 

 work is the presence of a denticulate hinge in Leptaena rhomhoi- 

 ■dalis, especially in shells of the younger or neanic stage, a struc- 

 ture hitherto unknown in this genus. The wonderfully well- 

 preserved impression of the brachial arms in the same species of 

 Leptae?ia is also figured and described here for the first time from 

 Australian rocks; and the brachial supports of one of the specimens 

 tends to show affinity with the chonetine structures in similar valves 



• of the Productidae. 



For some of the fossiliferous material included in the piesent 

 ■paper the writer is indebted to Mr. W. S. Dun, F.G.S., of Sydney, 

 who, some years ago undertook to describe Mr. G. Sweet's collection 



• of Silurian fossils, but who, after my arrival in Australia, generously 

 and insistently passed on the collection to be worked out in tlie 

 National Museum ])y myself. Consequently upon this, Mr. S\vt'"t 



'-iias consented to donate the <lescril;ed specimens as they are dealt 

 with from time to time. 



