932 PELECYPODA. [Eulumdlibrunchia. 



well marked, the margins smooth. Hinge with a triangular resilifer 

 under the beaks ; right valve with 2 divergent strong and elevated 

 cardinals, the anterior with a pectinated edge ; left valve with 2 

 dorsal narrow laminae, the posterior of which is triangularly ele- 

 vated. Adductor -scars fairly large. Pa/Hal line simple, distant from 

 the margin. 



Diameter Ant. -post., 7*2 mm. ; dorso-ventral, 5 mm. : thickness. 

 3 mm. 



Type in my collection. 



Hab. Hauraki Gulf, type (H. 8.) : Cuvier Island, in 38 fathoms 

 (Captain Eollons) ; Titahi Bay, Cook Strait (Miss Mestayer) ; Tau- 

 maki Island, in 10 fathoms ; Port Pegasus, Stewart Island, in 18 

 fathoms ; Snares, in 50 fathoms (Captain Bollons) ; Dusky Sound, 

 in 30 fathoms (R. Henry) ; Chatham Islands. 



Genus 8. CYAMIUM, Philippi, 1845. 



Cyamium, Philippi, Arch. f. Naturg., i, 1845, 50. Type : C. antarcticum, 

 Philippi, from Patagonia. Not Cyninium, H. and A. Adams. 1857, nor nf 

 Jeffreys, 1863. 



Shell small, thin, smooth, ovate, with an obsolete amphidetic 

 ligament externally, and a short strong oblique internal resilium ; 

 hinge-plate narrow, with in the right valve 2 subumbonal divari- 

 cating bifid cardinals, and in the left valve 3 more slender, not 

 obviously bifid, cardinals ; laterals none in either valve ; pallial 

 line narrow, except near the posterior muscular impression, where 

 it is irregularly wider or slightly insinuated ; adductor-scars narrow, 

 elongate ; margins of the valves entire. (Dall.) 



Distribution. Antarctic. 



1. Cyamium oblongum, E. A. Smith, 1898. Plate 54, figs. 6, a, b. 

 Cyamium oblongum, E. A. Smith. P. Mai. S., iii, 1898. 24, f. 8, 9 in text. 



Shell elongate, very inequilateral, moderately convex, thin, white. 

 Anterior end very short, acutely rounded, dorsal margin descending ; 

 posterior end long, broadly rounded, dorsal margin very little arcuate, 

 horizontal ; ventral margin lightly rounded. Sculpture consisting of 

 fine incremental lines. Colour white, light-brownish posteriorly. 

 Interior white, fulvous above, shining. Hinge : Right valve with 1, 

 left valve with 2 unequal teeth. Internal ligament narrow, slightly 

 oblique. Adductor-scars : The anterior scar moderately deep, the 

 posterior inconspicuous. 



Length, 5 mm. ; height, 3 mm. ; diameter, 2-5 mm. 



Type in the British Museum. 



Hab. Macquarie Island (A. Hamilton). 



Remark. A good series of specimens should be re-examined. 



