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

100 COLLECTIONS FROM MELAjnESIi..and bifid, and two in the left, of which the anterior is the larger andbifid. A single lateral tooth occurs in the right valve on each sidenot far from the cardinals, with a groove between them and themargin. Left valve with a slight tooth-like projection on the marginon each side fitting into the grooves in the other valve. ThepaUial sinus is large and deep. Internal cartilage minute, narrow,oblique, posterior to the cardinal teeth. External ligament small.The largest specimen measures 13 millim. by 9g. T. alba of Woodis somewhat like this species, but is more acute posteriorly, thedetail of its dentition is different, and the cartilage larger.27. Mactra eximia.{Deshayes) ;Reeve, Conch. Icon. fig. 31 (rayed variety).Hah. Port Denison, Queensland ( Coj^pmr/er) ; Port Curtis, MoretonBay {coU. Gaming) ; JN".E. coast of Australia {Brit. Mus.).There are altogether eight specimens of this species in the Museum,three of them being ornamented with numerous reddish rays, andthe remaining five uniformly white beneath the greyish and yellowishepidermis.28. Mactra producta, var.Spisula producta, Anyas, Proc. Zool. Soc. 1867, p. 900, pi. 44. tig. 7.Hab. Port Jackson (Angas and Coppinger).The three shells dredged by Dr. Coppinger are probably a varietyof this species. They are all small, apparently immature, and difterfrom the types presented to the Museum by Mr. Angas in beingless produced posteriorly. They are proportionally longer from theumbones to the ventral margin, which exhibits a very faint incurvationnear the hinder extremity, and the posterior dorsal slope is atrifle more arcuate.29. Mactra (Oxyperas) coppingeri. (Plate VII. figs. D-D 2.)Shell transversely elongate, triangular, a little inequilateral,rather compressed, thinnish, narrowly gaping posteriorly, smoothtowards the beaks, concentrically plicately ridged elsewhere, white,covered with a pale yellowish epidermis, spotted somewhat sparselythroughout with brownish dots, and ornamented on the dorsal areaswith cross lines of a deeper brown, and with a large patch of thesame colour on the hinder slope of each valve. Umbones moderatelyacute, not large, inclining towards and situated a trifle in advanceof the centre. Lunule sunken, not circumscribed by acute edges,extending more than halfway down the anterior slope. Posteriorlonger, smoothish, not mucharea as deep as the lunule and a trifleafi^ected by the terminations of the concentric ridges. Two lateralteeth on each side in the right valve, separated by a deep groovequite approximated to the cardinal teeth in front and the cartilagepitbehind. The latter is large, deep, and located posterior to thebeak. The cardinal tooth is small, insignificant, bounds the ligament,and has a cross piece above it immediately beneath the apex of the