N'OV 28 1893 



PHOLAS OBTUEAMENTUM. — HEDLEY. 55 



PHOLAS OBTURAMENTUM ; an UNDESCRIBED 

 BIVALVE FROM SYDNEY HARBOUR. 



By C. Hedley, F.L.S. 



[Plate XIV.] 



In the course of a critical examination of various Mollusca 

 from Port Jackson, specimens of the only Pholas reported thence 

 passed under review. This species has hitherto been accepted as 

 P. similis by all writers and collectors who have occupied them- 

 selves with the marine mollusca of our coast. This identification 

 appears to have originated with G. F. Angas, who in his " List of 

 additional Species of Marine Mollusca to be included in the 

 Fauna of Port Jackson and the adjacent Coasts of New South 

 Wales,"* enumerates as species 93 : — 



"Barnea similis. Pholas similis, Gray, MS. Brit. Mus. ; Thesaurus 

 Conch, pi. ciii., f. 12-14; 'Bottle and Glass' rocks, in 

 sandstone (Brazier)," 



This entry is repeated verbatim by Mr. T. White! egge in the 

 " List of the Marine and Freshwater Invertebrate Fauna of Port 

 Jackson and the Neighbourhood. "f Mr. Bi'azier informs me 

 that this determination was also supported by the late G. B. 

 Sowerby. 



Prof. Tate records Barnea similis, Gray, J as "burrowing in clay 

 at low tide mark, Port Lincoln, St. Vincent Gulf, and south-east 

 coast [of South Australia] ; also in Tasmania." 



On examining the statement of Angas closely, our faith in his 

 accuracy is weakened by observing that Gray's name was not, 

 as he states, a manuscript one. It was first published with a 

 description in 1835 in the Appendix of Yates' New Zealand, 

 p. 309, and it again appeared, with further information, eight 

 years later, in Vol. ii. of Dieff"enbach's New Zealand, p. 254 

 where the author remarks that it is " very like Pholas parvus, but 

 larger, broader, and more acute in front." 



Between the New Zealand and the Australian species a dis- 

 crepancy at once appears on comparing examples of the Port 



* Proc. Zool. Soc, 1871, p. 99. 



t Journ and Proc. Koy. Soc. N.S.W., xxiii. (1889), p. 234. 



X Trans. Soy. Soc. S. Australia, iz., p. 80. 



Sept. 1893J 



