Report on the zoological collections made in the Indo-Pacific Ocean ...

MOLLtJSCA. 109twice as many, and produce a denticulate margin to the valves.Interior slightly iridescent. Umbones small, glossy, not radiatelysculptured like the rest of the shell. Length 6 millim., height 3-|,diam. 3.Hah. Dundas Straits.This is a very prettily sculptured species, approaching, as regardsoutline, M. varicosa. It is, however, quite distinguishable by thegreater coarseness and subgranular character of the radiating anteriorand posterior ridges.The single specimen described above may not be full-grown ; butI conjecture it never attains a much larger size.53. Modiolaria varicosa. (Plate VII. figs. M, M 1.)Goidd, Proc. Bost. Soc. Nat. Hist. 1861, vol. viii. ; Otia Conch, p. 176.Hah. Port Jackson ( Coj929iHfjrer) ; Sydney (&'o?tZ(:^).This pretty little species was figured by Reeve (Conch. Icon. fig. 83)as the young of Modiola str'igata, Hanley ; and this must have inducedGould to observe that it '' is marked like " that species, forin reality there is very little resemblance in the painting of the twoshells. The radiating sculpture is faintly indicated in the abovefigure by means of scratched lines, but these are only noticeableunder a lens.54. Lithodomus teres.Modiola teres, Philipjn, Abbild. vol. ii. p. 148, pi. 1. fig. 3.Lithodomus teres, Peeve, Conch. Icon. fig. 13.Hab. Pacific Ocean (Phil.): Philippine Islands (Cuming); PortDeuison, Queensland (Coppinger).The anterior perpendicular strise are rather coarse in this species ;the raised interstices between them are very conspicuous at themargin, and gradually become finer as they ascend the valves, sometimesfurcating at one or more of the concentric lines of growth.The interior is pinkish or bluish, and more or less iridescent.55. Area navicularis.Bruguiere; P/nlijjpi, Abbild. vol. ii. pi. 3. fig. 2; Peeve, Conch. Icon.fig. 70 ; Wood, Index Test. pi. 9. fig. 5.Var. =Arca linter, Jonas, Philippi, I. c. fig. 1.Var.=Arca subquadrangiila, Dimker, Philippi, I. c. fig. 3.Var. = Area cvmiingii, Dunker (MS. in coll. Cuming) ; Adams, GeneraMoll. ii. p. 533.Hah. Port MoUe, Queensland (Copjjzn^er) ; Port Phillip, China,Cape Capricorn, Amboina (Brit. Miis.).The varieties respectively called A. linter and A. suhquadrangulaare distinguished only by very variable characters, such as form andthe amount of ligament, which in this group of Arks are of littlevalue.