738 STUDIES ON AUSTRALIAN MOLLUSCA, xii., 



Arcularia particeps, sp.nov. 



Nassa suturalis Forbes, Voy. Rattlesnake, ii., 1852, p. 365; Id., 

 var., Reeve, Conch. Icon., viii., 1853, PI ii., figs. 11a, lib; Id., 

 var., Angas, Proc. Zool. Soc, 1867, p. 190; Id., var., Marrat, 

 Variation of Sculpture in the genus Nassa, 1877, PI. i., fi^.3; 

 Nassa, glans var. suturalis Watson, Ghall. Zool., xv., 1886, p. 179. 

 Not Biiccinum suturale Lamarck, Anim. s. vert., vii., 1882, p. 269, 

 and Kiener, Coq. Viv., Buccinum, 1834, p. 54, PI. 24, fig.96. 



Nassa intermedia Angas, Proc. Zool. Soc, 1877, p. 180, op. cit., 

 1878, p. 865; Nassa glans var. intermedia Whitelegge, Proc. Roy. 

 Soc. N. S. Wales, xxiii., 1889, p. 248. Not Alectrion interm^edia 

 Frauenfeld, Novara Exped. Zool. Moll., 1867, Pl.i.,fig.2. [Preocc, 

 Forbes, Rep. Brit. Assoc, 1843(1844), p.l90; replaced by N. 

 suturalis dunkeri Suter, Trans. N. Z. Inst., xl., 1907(1908), 

 p.350]. 



Nassa glans Pritchard & Gatliff, Proc. Roy. Soc. Vict., x,, 

 1898, p.280. Not Buccinum glans Linne, 1758. 



A shell, common on this coast, was first noticed by Forbes, 

 under the incorrect title of Nassa suturalis, as having been taken 

 in 6 fathoms in Port Jackson by H.M.S. " Rattlesnake." This 

 Sydney shell has features in common both with A. glans Linne, 

 (as shown by Kiener's fig. 52) and with A. suturalis Lamarck, (as 

 shown by Kiener, fig.96), to each of which it has been in turn 

 referred, but from each of which it consistently differs. In form 

 and painting, it closely resembles A. suturalis, but differs, as 

 Angas observed, by lacking the characteristic sutural bead-row, 

 in which feature it approximates to A. glans. The prickles on 

 the anterior outer lip, possessed both by A. glans and A. suturalis, 

 are evanescent in A. particeps, which is more slender than either, 

 and has a broad sutural shelf or gutter. 



This Sydney shell is about 30 mm. long and 15 mm. broad; it 

 has been figured by Reeve as "A light variety of N. suturalis," 

 and by Marrat as "A narrow variety of N. suturalis.'^ 



A species with subsutural nodules, localised as from Sydney, 

 was described in 1866 by Dunker and Zelebor as Alectrion inter- 

 media, and figured by Frauenfeld the following year. Pease* 

 * Pease, Amer. Journ. Conch., vii., 1872, p.23. 



