BY C. HEDLKY AND A. F. liASSKT HULL. 275 



Remarks. — This shell is extremely common, and appears to 

 occupy a position intermediate between 1. crispus Reeve, of Aus- 

 tralia, and /. longicymha Quoy, of New Zealand. Compared 

 with /. crispus, the novelty is more elevated, has more definitely 

 sculptured lateral areas, and is especially disting'uishable from 

 both /. crispus and J. Jongicymba by the extremely minute girdle 

 scales. 



A similar, if not identical, species was found by Mr. T. Iredale 

 on Raoul or Sunday Island, Kermadec Group.* 



\. ACANTHOCHITES LKUCONOTUS, n.sp. 



(Plate xii., figs. 4, 4a, 46, 4t', \d, ie, if.) 



Shell elongated, valves carinated. Colour white, 5th and 6th 

 median valves frequently with green spot on each side, the tip 

 and sometimes the valve suffused with pink. 



Anterior valve with 5 strong radiating pustulose costte. 



Posterior valve similar to median valves, but without the pro- 

 minent rib. 



Median valves : latero-pleural areas irregularly pustulose, the 

 pustules on the lateral areas lai-ger and less in number than those 

 on the central areas; the two areas separated by a ray of pro- 

 minent pustules which increase in size towards the margin. 



Jugal tract not elevated, margined with pustules, V-shaped, 

 transversely striate. 



Girdle broad, beset with short white spicules, and having 9 

 bunches of long white spicules on each side. 



Interior pearly-white, sinus broad, shallow. Anterior valve 

 having 5, and median valve 1-1 slits. The posterior valve has 3 

 almost obsolete slits, edge thickened. 



Length 12nnn., breadth 5"5 mm. 



Station. — On the under side or at the edge of the insertion in 

 tlje sand of small smooth stones, in pools or channels, at low 

 tide. 



Habitat. — Lord Howe Island. 



* Iredale, I'luc. Malac. Sue. ix., 1910, p. 161. 



