BY C. HEDLEY. 685 



dorsal angle is a particularly long, slender horn. Similar pro- 

 cesses on the mantle are shown in a sketch of Scintilla chilkaensis 

 Preston.* Posteriorly, the mantle develops into two voluminous 

 flaps. This gregarious species shelters under stones at low water 

 in the mud-zone in Middle Harbour, Sydney, in companies of a 

 dozen or so. 



Following the identification of G. F. Angas, this species has 

 locally been received as Scintilla anomala. But it does not agree 

 with the figure of that species in the Thesaurus; and Mr. H. B. 

 Preston, who compared the type in the British Museum with 

 Sydney specimens, assures me that they are distinct. 



Cardium rackettii Donovan. 



Cardium rackettii Donovan, Naturalist's Repository, iv., 1826, 

 PL 124. Cardium radiatum Reeve, and Cardium pallidiim 

 Reeve, Conch. Icon., ii., 1845, PI. xviii., figs.89, 92. Cardium 

 tenuicostatum of authors, but not of Lamarck and Delessert. 



No mention is made of Cardiiim rackettii in any of the mono- 

 graphs or catalogues dealing with the genus Cardium. Yet it 

 was excellently figured, described, and localised, as being the 

 size of the ordinary European Cardium echinatum, having 47 

 ribs, and obtained by Humphrey in New South Wales. It is 

 obviously a species common round Sydney, a particularly fine 

 example of which befoi-e me, from the Harbour, is 48 mm. in 

 height and in breadth, and has 49 ribs. By Forbes, it was 

 reported from Sydney as C. radiatum, and, by both Angas and 

 Smith, as C. tenuicustatum.J 



But Cardium tenuicostatum was described by Lamarck from 

 Timor and New Holland as a shell 56 mm. in diameter, with 48 

 ribs. The figure which Delessert gave (PI. xi., fig.6) from a 

 Lamarckian specimen exhibits a shell of a quite different contour 

 from C. rackettii, and disagrees with the figures which Sowerby, 

 Hanley, Ueeve, and Roemer have produced as of C. tenuicostatum. 

 It is now suggested that the real C. temiicostatum has been lost 



* Anuandale and Kemp, Mem. Indian Museum, v., lUlU, p.3.51. 

 t Forbes, Voy. Rattlesnake, ii., 1852, p. 366. Angas, Proc. Zool. Soc, 

 1867, p.925. Smith, Chall. Rep. Zuol., xii., 1885, p.l59. 



