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Notes on south Australian Marine Mollusca, 

 WITH Descriptions of New Species. -Part XII. 



By Jos. C. Verco, M.D. (Lond.), F.R.C.S. (Eng.). 



[Read October 5, 1909.] 



Plates XXVI. to XXIX. 



My paper contains descriptions of new species belonging 

 to various genera, but consists chiefly of a revision of the 

 Pleurotomidcc. Mr. G. F. Angas wrote a paper on the 

 "Marine Molluscan Fauna of South Australia" in the Pro- 

 ceedings of the Zoological Society of London for 1865, p. 

 155, in which he recorded 11 species, and 6 more in another 

 short one in 1880. In 1893 Mr. Adcock in his "Handlist 

 of the Aquatic Mollusca of South Australia" enumerated 20 

 species. In 1896 I sent to Mr. Sowerby examples of all 

 species belonging to this family, which had been dredged by 

 me during several years in South Australian waters up to 

 23 fathoms. He wrote a paper on them, which appeared in 

 Proceedings of the Malacological Society of London, vol. 

 ii., p. 24, and created 17 new species, and revised our pre- 

 vious lists, and brought the number up to 33. Since then 

 my dredging has been extended to three hundred fathoms, 

 and material of quite a different character has been collected. 

 This has furnished examples of several shells previously re- 

 gistered for Victoria, Tasmania, and New South Wales, and 

 especially of species from the deep dredgings of Mr. Hedley 

 faid Mr. May, together with quite a number unknown hither- 

 to. This material has been submitted to these two gentle- 

 men and Mr. Gatliff , who have very kindly identified several 

 species from types in their possession or in their State 

 Museums, and have furnished very helpful suggestions, for 

 which I record my thanks. 



The group has proved very difficult, chiefly owing to a 

 wide variation, which affects so many of the species, and 

 also to the rather indefinite character of not a few of the 

 genera, making one uncertain as to their limits. In a few 

 instances only has the animal been examined, and some fea- 

 ture been detected by which the shell may be more surely 

 located. 



Our family has now grown to the respectable number of 

 79 species, with 10 named varieties. 



