REPORT ON THE LAMELLIBRANCHIATA. 153 



marginata. CarJo Icvis, aiigustus, dentibus tcnuil)us raunitus. Ligamentum angustum, 

 clongatum, couditum, omniuo internum. Pallii siuus angularis, apice truncato, usque ad 

 medium valvje prolongatus. Cicatrix antica elougata, angusta, postica paulo latior, 

 superne lobata. 



The shell of this pretty species is rather thin, longer than high, transversely roundish 

 ovate and a little inequilateral, the anterior side being the shorter. It is dull chalky 

 white, very finely and closely concentrically lirate, and lamellated and radiately sculptured 

 in the interstices with minute and very close substrife. The lamellse are excessively thin, 

 fragile, not much elevated, and more or less broken in many places, giving the surface a 

 very ornamental appearance. Upon the most convex portion of the valves, and towards 

 the urabones, they are for the most part worn down, and there take the form of fine lira3. 

 The lunule is moderately deeply sunken, cordiform, with straightish sides, elevated along 

 the middle, and sculptured with fine lamellas of growth. The posterior area is not very 

 apparent, narrow, raised along the dorsal margin and defined by an indistinct shallow 

 depression on each side. The umbones are moderately elevated above the hinge-plate, 

 well curved over towards the front, glossy and finely concentrically striated at the apex. 

 The outline of the valves is regularly curved all round except upon the dorsal margins, 

 which are somewhat straight, the anterior being rather more oblique than the posterior. 

 The ligament is altogether internal, narrow, and long. All the teeth are slender, the 

 central one in the left valve being remarkable in this respect and widely divergent fi-om 

 the thin, erect, anterior tooth. The pallial sinus is deep, extending obliquely upwards a 

 little beyond the middle of the valve ; its sides are straight, converging, and the apex is 

 truncated. The front muscular scar is long and narrow, the posterior a little broader, 

 having a little lobe at the upper end. 



Length 33 mm., height 28^, diameter 17. 



Habitat. — Station 189, south-west of New Guinea, in 25 fathoms ; green mud. 



Dosinia sculpta (Hanley). 



Artemis sculpta, Hanley, Cat. Eec. Biv. Shells, Append., p. 357, pi. xv. fig. 42 

 Artemis sculpta, Sowerb}% Tlies. ConcL, vol. ii. p. 659, pi. cxli. fig. 15. 

 Artemis scul2^ta. Reeve, Conch. Icon., vol. vi. fig. 52. 

 Dosinia sculpta, Eomer, Monog. Dosinia, p. 38. 



Habitat. — Torres Strait, in 3 to 11 fathoms. 



Only a left valve of a young specimen was collected at the above place. At this 

 age the apex of the umbones is tinted with pale rose, which generally appears to fade 

 away as the shell arrives at maturity. There are specimens in the British Museum said 

 to have been obtained at Moreton Bay, Queensland, by Mr. Strange. 



(ZOOL. CHALL. EXP. — PART XXXV. — 1885.) Mm 20 



