REPORT ON THE LAMELLIBRANCHIATA. 183 



and fewer in number, and the radiating sculpture is also of a coarser character. The 

 constitution of the hinge is very similar, but in Lucina levukana the anterior lateral 

 teeth are more remote from the cardinals than in this species. The edges of the valves of 

 the latter are considerably thickened, and the denticles on the inner margin are fewer and 

 stouter than in the Fijian funii. 



Length 3| mm., height 3^, diameter 2^. 



Habitat. — Station 185b, east of Cape York, North Australia, at a depth of 155 

 fathoms ; coral sand. 



■Lucina (Codakia) hawaiiensis, n. sp. (PI. XIII. figs. 8-8a). 



Testa ineequilateralis, oblongo-rotundata, paulo obliqua, ante umbones exeavata, 

 antice late curvata, postice angustior, alba, lamellis tenuibus jjarum elevatis costeUisque 

 crassioribus radiantibus minus elevatis cancellata. Margo dorsi anticus ^Jrimo excavatus, 

 leviter declivis, posticus brevior, magis obliquus, rectiusculus ; umbones parvi, leviter 

 prominentes, incurvati, antrorsum versi. Lunula parva, subprofunda, pellucida. 

 Dentes cardinales duo in valva sinistra, unicus in dextra validus, triangularis, medianus. 

 Laterales fortes, subsequidistantes, posticis paulo propius umbones positis. Ligamentum 

 externum, supra marginem locatum. Pagiua interna alba, cicatricibus magnis notata, 

 ad marginem denticulata. 



A single specimen and an odd valve, which probably do not represent the adult state 

 of the species, are all that are at present known. 



The shell is rather thin, having a semipellucid appearance, of an oblong irregularly 

 rounded form, fairly convex, rather inequilateral, and somewhat oblique. The posterior 

 dorsal margin is short, almost straight, and rather sloping, the anterior being longer, less 

 oblique, concave at first, and then rounding into the broadly curved anterior end, which is 

 wider than the hinder extremity. The beaks are small, smooth, opaque white, incurved 

 over the small deepish pellucid lunule. The sculpture consists of slender slightly elevated 

 concentric lamellae which pass over less raised but thicker radiating costellse. The hinge 

 is composed of two cardinal teeth in the left valve and one in the right, and a small 

 ligament placed in a narrow groove on the hinder dorsal edge in each valve. All the 

 cardinals are strongish, those in the left valve being divergent, and separated by a 

 triangular pit, which receives the strong central tooth of the right. The lateral teeth, too, 

 are thickish and well developed, and moderately remote from the centre of the hinge- 

 plate, the anterior being a little more distant than the posterior. The inner margin of 

 the valves is rather coarsely dentate, the muscular scars are large, and the pallial 

 impression is simple. 



Length 3^ mm., height 2f, diameter 2^. 



