277 



NOTES ON South Australian Marine mollusca, 



WITH descriptions OF NEW SPECI ES.-PART XI. 



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



[Read October 5, 1909.] 



Plates XXII., XXIII., and Part XXYI. 



My paper deals with the genus TripJiora. I have 

 adopted this name, in accordance with the conclusion ar- 

 rived at by Mr. Hedley as to Blainville's priority of publi- 

 cation. 



Hitherto only four species have been recorded for South. 

 Australia, which furnished the type specimens of them all — 

 viz., T. angasi, T. f estiva, T. pfeifferi, all of Crosse and 

 Fischer, and T. scitnia, A. x^dams. Several others were 

 known to occur here, but their identification was difficult- 

 Mr. Hedley, in a valuable contribution to the Proc. Linn. 

 Soc. of New South Wales, 1903 (1902), on the Triphoridje 

 of that State, cleared away much of the obscurity which had 

 enveloped some already desci'ibed species from Port Jackson ;, 

 and added several new ones to the list. Specimens of nearly 

 all these, kindly supplied by him, have aided considerably 

 in unravelling the tangle of our South Australian forms. Six 

 of his eight novelties are represented here, and four of the- 

 six species described by other authors. The task has been 

 difficult, even with this clearance. A very large number of 

 shells, collected during several years' dredging, furnished 

 not only many species, but a most perplexing number and 

 series of variants in nearly everj^ species: and what with 

 macromorphs and micromorphs, juveniles and adults, nar- 

 row and obese forms, differences in relative size of pearl rows,, 

 validity and invalidity of the sutural thread, rolled, 

 bleached, or fresh shells, typical and atypical colouration, 

 accurate specific determination at times seemed unattainable. 

 Even now it is impossible absolutely to decide whether some 

 of my enumerated varieties are not distinct species, and some 

 of my newly-named species may not prove eventually to be 

 only variants. Of the four species enumerated in Adcock's^ 

 "Handlist of Aquatic Mollusca of South Australia," 1893, 

 one has been omitted, viz., T. scitidus, A. Adams. It was 

 described from a Port Lincoln shell, but .has not been re- ' 

 cognized. A shell which in some respects conforms to the- 

 description has been dredged, but I refrain at present from 

 so naming it. To the remaining three species we have been 



