MOLLUSCA-CONCIIIFERA.

227

far as to consider the position as oblique, with the anusdirected upwards and backwards, Blainville’s representation,which makes the hinge superior, should be preferred."With respect to the asymmetrical Conchifers, the author veryacutely observes, that they stand in the same relation to-wards the symmetrical as the Pleuronectce do to the rest ofthe fishes, and that, consequently, in them the valves are tohe distinguished not into left and right, hut into superiorand inferior. They are placed on the side. (Comptesrendus, xvi, p. 561, 1843; Froriep’s Notiz. xxvii, p. 193.)This innovation of D’Orbigny’s is attacked by Deshayes(Comptes rendus, xvii, p. 1333), and defended again by.TFOrbigny. (Ib. p. 1364.)

Templeton states that Avicula radiata , Leach, is the Pearl-oyster ofCeylon. It is figured, ‘Annals ’ xi, p. 325, pi. 7.

Menke describes (1. c.) a new Plicatula, P. imbricata , with scaled pli-cations.

Lima Cumingii and angulata, Sower. (Proc. p. 23), both figured in his‘ Thesaurus.’

Peden bifidus, Menke, the costse of the convex valve divided by agroove.

Two new species of Pinna are instituted by Menke (1. c.), P. virgata anddeltodes ; the latter from the mouth of Victoria River.

Krister contends (Isis, 1843, p. 565) for the dangerousassertion that in Europe numerous species of Unio andAnodonta should be distinguished. It is very possible thatan accurate study and careful discrimination would be ofgreat utility, but the numerous European species adducedcan only be regarded, in my opinion, as local varieties of afew species. This is not the place to carry out this viewfurther, and it is here merely referred to.

Unio bigerrensis (Guerin, Mag. pi. 64), testa pseudo-elliptica, crassa, nonhiante, posterius bicolorata, oblique truncata; radiis viridibus aut-rufescen-tibus divergentibus : natibus decorticatis erosissimis; dentibus cardinalibusbrevibus crassis, sulcatis, et dentatis non regulatim, laterali acuto lamelloso.U. manca id. (ib.), testa oblonga reni-formis, natibus prominulis, non decor-ticatis, undato-rugosis. Both from Prance. U. panacoensis, v. d. Busch inPhilippi (Heft 2), is a beautiful large species from the river Panaco, nearTampico .