MOLIiXFSCA. Ill 



particularly conspicuous at the paUial line, wtere they terminate. 

 The muscular scars are large, well defined by a line radiating from the 

 umbones. Hinge-teeth rather numerous, miaute in the centre, 

 considerably larger at both ends. In the type there are forty, and 

 a specimen about half-grown has thirty-five. The ligament is 

 narrow, but very coarsely striated transversely. The epidermis is 

 thinnish and somewhat fibrous near the margins, especially pos- 

 teriorly. 



59. Area (Barbatia) symmetrica. 



Area symmetrica, Reeve, Conch. Icon. sp. 117, and fig. 120. 

 ?Var.=Aica zebuensis, JReeve, I.e. fig. 117, sp. 120. 



Hob. Port MpUe, Queensland, 12-20 fms. (Goppinger) ; Bay of 

 Manila (Ouming'). 



In the ' Conohologia Iconica ' the numbers of the figures 120 

 and 117 should be reversed. The specimens of A. symmetrica 

 which were described by Eeeve are of a greenish tint, and not so 

 oblique as A. zebuensis. The sculpture in both consists of fine 

 radiating lirse, rendered minutely granular by the concentric lines 

 of growth. The lirse vary but little in thickness, with the excep- 

 tion of a few finer intermediate ones here and there apd those on 

 the posterior extremity, which are a trifle stouter. A. zebuensis 

 differs, in addition to its extra obliquity before referred to, resulting 

 from the less central position of the umbones, in being a trifle more 

 finely lirate. One of the specimens from Port MoILe is somewhat 

 intermediate in form, being more oblique than A. symw^etrica and 

 less so than A. zebuensis. The measurements of two specimens will 

 indicate to what extent the form and proportions may vary : — 



No. 1. Height 7-^ miUim., length 11, diameter 8. 



No. 2. „ 6i „ „ 11, „ 6i. 



60. Area (Trisis) tortuosa. 

 Area tortuosa, Linn. 



Hah. Singapore and Malacca {Cuming); North-west Australia 

 (Dm Boulay) and China (Beeves), in Brit. Mus.; Port Curtis in 

 11 fms., sand and shell bottom {Coppinger). 



The right valve of this weU-known and remarkable shell always 

 appears to retain more of the epidermis than the left. The foot and 

 mouth of the animal, as might be expected, are at the narrow end 

 of the shell. The foot (in spirit) is small, narrow, and grooved 

 beneath, retaining a small byssus. 



61. Leda darwini. (Piaie VII. figs. L-L2.) 



Shell a little inequilateral, rather convex, transversely irregularly 

 ovate, acuminate posteriorly, thinnish, glossy, moderately coarsely 

 concentrically ridged and sulcate throughout, except upon the lunule 

 and area, the ridges being finer and the sulci broader on -a slightly 

 depressed portion of the surface down the posterior side, which is of 



