[Pkoc. Roy. Soc. Victoria, 25 (N.S.), I't. II-, li)13.] 



Art. XXIX. — On a New SUurlan Bivalve from the Lilydale 



Quarries, Liteind. (Probicina) mifcludli. 



By G. B. PRITCHARI), D.Sc, F.d.S. 



(Lectiuvr in lieology, &c., School of Mines Departmeut, Working? 

 Meu's College, Melbourne). 



(With Plate XXIX.). 



[Read 12th December, 1912.] 



Lilydale is a well known locality for well-preserved fossils of 

 very high antiquity, namely, silurian, and the Cave Hill Quarries 

 have been yielding up their treasures to diligent searchers for 

 quite a number of years. A glance at the list of fossils from this 

 locality will, however, show that we have at present rather a 

 scanty knowledge of its bivalved molluscan fauna, as the record 

 includes only six species. 



Any additional information should therefore be of some interest 

 and value, and it is with pleasure that I now make the record of 

 a new sj^ecies. 



During a recent visit to the Cave Hill Quarries, my assistant, 

 Mr. Stanley R. Mitchell, had the good fortune to discover a very 

 fine and perfect specimen of a large bivalve, which evidently belongs 

 to the family Lucinidae. This specimen he has very kindly placed 

 in my hands for description, and I take this opportunity of tender- 

 ing him my thanks and of naming the species after him. 



Lucina (Prolucina) mitchelli, sp. nov. 



Dcsm pfion. — Shell orbicular, tumid, beak small, depressed, con- 

 vexly rounded and situated at about one-third of the diameter fiom 

 the anterior margin; lunulc narrowly cordate, very small but dis- 

 tinct. Anterior margin regularly convexly rounded, from the lunule 

 to the ventral margin, the latter becoming distinctly straighter as 

 it reaches up to the posterior margin; posterior truncation makes 

 an obtusely angular junction with the ventral margin of about 

 110 degrees, and runs obliquely upwards to join the convex posterior 

 dorsal margin. Tlie shell sliows its greatest tumidity slightly to 



■23a 



