480 



STUDIES ON AUSTRALIAN MOLLUSCA, X. 



grains of nearly uniform size are crowded in close spiral rows. 

 On the last whorl are eighteen, on the penultimate seven, and on 

 the antepenultimate six bead rows. Two or three spiral threads 

 run along the shallow interstices which intervene between the 

 rows. Aperture oblique, deltoid, choked by intrusions from right 

 and left. From lip to lip a smooth thick but translucent callus 

 spreads round the perforation. The very oblique columella arises 

 deep within the perforation, and ends in a large projecting 

 triplicate tubercle (the left intrusion); above the tubercle is a fold, 

 and above that a small denticle. The opposite intrusion is a 

 massive tricuspid rooted within the margin of the lip, and hang- 

 ing deep into the aperture. On the palate between the perfor- 

 ation and right insertion are three short entering bars, followed 

 by another winding far into the interior. Inside the periphery 

 are three long entering infrapalatal ridges alternating with short 

 ones at the entrance. Basal margin with half-a-dozen short 

 transverse folds. Height, 18; maj. diam., 20; minor diam, 

 17 mm. 



Greater size and paler colour are the features which separate 

 C. albinus from C. clanguloides Wood. 



Monodonta sulcifera A. Adams. 



A. Adams, Proc. Zool. Soc. 1851 (1853) p. 175. 

 The cotype of this unfigured species, lent me by the British 

 Museum, represents an immature Euchelus atratus Gmelin. 



Cantharidus suturalis A. Adams. 



Thalotia suturalis A. Adams, Proc. Zool. Soc. 1851(1853), p. 173; 

 Ann. Mag. Nat. Hist. (2), xii. Sept. 1853, p.204. 



(Plate vii., fig.4.) 



Shell small, solid, pyramidal, imperforate. Apex eroded, but 

 whorls apparently six, flattened, slightly gradate, last descending 

 a little at the aperture. Colour pale yellow, tessellated with 

 small purple spots. Sculpture : low, flat-topped spiral ribs equal 

 to the intervening spaces, on the last whorl twelve, of which half 



