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

;106 COLLECTIONS FROM MELAjSHESIA.before me gradations in respect to lengtli and breadth, Botb areslightly narrower in front than behind, sculptured with fine concentricstrico and more or less indistinct shallow radiating markings,a feature unnoticed by Deshayes. Although the dentition isdescribed by that author as somewhat different, I am bound to say,after a most careful examination, that both the number and positionof the teeth are absolutely similar. In the left valve I find threeteeth, the anterior one being very small at the termination of theinner margin of the hinge-plate, which is grooved on both sides ofthe beak. The central tooth is large, prominent, situated immediatelybeneath the point of the umbo, and the third is insignificantand posterior to the narrow oblique ligament. The right valve hasa large prominent tooth a little in front of the apex of the umbo,and generally the extremity of the inner edge of the grooved hingeplateis raised into a tooth-like prominence behind the ligament,which extends not only within the valves, but also along the hingelinejust above the teeth. The single specimen from Port MoUe andone in the Cumingian collection are peculiar in having two or threeof the shallow radiating impressions towards the hinder ventral extremitydeeper, thus producing a wavy margin to the valves at thatparticular spot.47, Scintilla aurantiaca. (Plate VII. figs. H, H 1.)Beslimjes, Proc. Zool. Soc. 1855, p. 179 ;p. 176, pi. 234. fig. 5.Soiuerby, Thes. Conch, vol. iii.Hah. North Australia, under stones at low water (Jul-es) ; islandof Nairai, Fiji, at low water (Brit. Mas.) ; Port MoUe, Queensland(Coppinger).The specimens from Port Molle agree precisely with the types ofS. aurantiaca in the national museum. There are some other specieswhich I cannot distinguish from it; these are S. faha, Desh., S.Forhesii, Dash., S. pallidula, Desh., S. amhir/iia, Desh., S. borneensis,Desh., and S. adamsi, Desh. The last and S. faha are placed bySowerby in the group of " species with no hiatus " in the ventralmargin. This location is incorrect, for both gape slightly, and infact Deshayes, in his description of the latter, says " margine inferioreangustissme hiante." This opening appears to be subject tovariation in shells which are unquestionably the same specificallyand therefore I believe it probable that all the above-mentionedso-called species will prove to be variations of Lamarck's Psammohiaaurantia, which, according to Sowerby's figure (Conch. Icon,fig. 20, S. maiiritiana), has an extremely wide gape beneath. Thelatter species is said to be synonymous with S. aurantia by Deshayes(Anim. sans Vert. vol. vi. p. 180, GaJeomma aurantia), and vonMartens expresses a similar opinion (Miibius, ' Meeresfauna Mauritius&c.,' p. 322). Deshayes (P. Z. 8. 1855, p. 167) says that the Lamarckianshell is a Galeomma.The animal of Dr. Coppinger's shells agrees with the description