753 



MELANIA. 



MELANOPSIS. 



75 i 



by a buccal slit which is small and longitudinal ; one pair of tentacles 

 elongated, filiform, carrying the eyes on the external side, sometimes 

 near the base, sometimes towards one-fourth of their length ; mantle 

 open, with festooned edges ; operculum horny, elongated, and narrow, 

 with an apical and paucispiral summit. (Deshayes.) 



Shell with an epidermis, of an oval obloug, a pointed spire, which 

 is often elongated or turriculated, and an oval aperture which is 

 widened anteriorly, aud has a very sharp edge. 



It inhabits the rivers of warm climates generally, and of Asia 

 especially. Species are also recorded from Africa and North and 

 South America. Mr. Conrad has described several new species from 

 the rivers of Alabama. 



M. Deshayes thus divides the Melania : 

 a. Shell oval or sub-turriculated. 



Ex. .'/. amarula. 



Melania amarula. 



0. Shell elongated, turriculated. 



Ex. M. truncata. 

 y. Shell with the inferior angle detached. 



Ex. M. coitdlala. 

 8. Shell with a bordered aperture. 



Ex. M. marginata and M. lubvlata. 



.Vrlania subulata, 



Lamarck gives the rivers of the East Indies, Madagascar, the 

 Mauritius, &c., as the locality of M. amarula, the animal of which, 

 he says, is very bitter, and passes for an excellent remedy for the 

 dropsy. 



The apex of all the species is generally eroded as the animal 

 advances in age. 



Woodward, in his 'Manual, 1 says, there are 160 recent species, 

 The following are sub-genera :Melanatria, Bowdich ; Vikex, Oken; 

 Ceriphaiia, Sw. ; Jlcmisinue, Sw. ; Melafiunt, Sw. ; Melatoma, Anthony; 

 Anculotun, Say; Amnicola, Anthony; and Pachystoma, Gray. 



Fouil Melanin. M. Deshayes, in his ' Tables' (Lyell, 1838), makes 

 the number of living species 34, and the number o"f fossil (tertiary) 

 25. The ppecies recorded as both living and fossil (tertiary) are 

 Melania inqmnata, M. injlesca, M. Cambessedetii, and a new species. 

 The habitations allotted to the living species of M. inqmnata, M. 

 inflexa, M. Cambettedesii, and the new species, are the Philippine 

 Isles, the Mediterranean, and the lakes of Como and Geneva. M. 

 looted, M. nitida, and M, costcllata are noticed as fossil species found 

 in more than one tertiary formation. In the last edition of Lamarck 

 (1838) the number of recent species in 36, and of these M. inqmnata 

 only is noted as occurring in a fossil state. The number of fossil 

 species recor.icd in this edition is 8, and of these M. Deshayes notes 

 the species M, coslellata, M. maryinata, and M. nitida as not being 

 Melania, M. nitida having all the characters of the genus Eulima. 

 The other two M. Deshayes keeps provisionally among the Melania;. 

 Melania $emipiicata, another of the eight, he conceives to be a variety 

 of M. lactea, and is of opinion that it should be expunged from the 

 catalogue. 



HAT. HIST. D1V. VOL. III. 



Dr. Mantell records two species (M. sulcata and M. costellata ? ) in 

 the Blue Clay of Bracklesham. Professor Phillips notes a Melania (?) 

 in the Speeton Clay, and two species (M. Heddinytonensis and M. 

 striata) in the Coralline Oolite, M. Heddingtonensis and M. vittata iu 

 the Corubrash, and M. Heddinytonensis and M. striata in the Bath 

 Oolite. Iu the table at the end of his work (' Geology of Yorkshire') 

 he records Melania striata in the Coralline and Bath Oolite, M. Hcdding- 

 tonensis iu the Coralline Oolite, Cornbraah, and Inferior Oolite, M 

 lineata in the inferior Oolite, aud M. vittata, in the Coralline Oolite 

 and Cornbrash. Dr. Fittou records Melania Heddingtonensis in the 

 Oxford Oolite (Dorset and Oxford). 



MELANIAD^E, Melanians, Lamarck's name for a family of fluvia- 

 tile, testaceous, operculated Mollusca, breathing water only, and 

 belonging to the order Trachelipoda. The family consists of the genera 

 Melania, Melanopsis, and Pirena, according to Lamarck, aud Mr. G. B. 

 Sowerby, Jun. (' Conchological Manual '), suggests that to these may 

 be added Anculosa and Pasitluva. M. Debhayes, iu the last edition of 

 Lamarck, adds the genera Eulima and Bissoa to Melania, Melanopsis, 

 and Pirena, the hitter of which, it seems, should be expunged. In 

 Woodward's 'Manual of the Mollusca' the Melaniada; include the 

 genera Melania [MELANIA.], Paludomus, and Melanopsis. [MELAN- 

 Orsis.] 



MELANITE. [GAKNET.] 



MELANOCHLORITE, a native Chromate of Lead, containing 

 23'64 of chromic acid. It has a dark-red colour, .with a brick-red 

 streak. It occurs in tabular crystals reticulat-.-ly arranged. It conies 

 from Siberia. 



MELANOPSIS, a genus of fresh-water Testaceous Turbinated 

 Mollusca, to which Lamarck assigns a position among his family of 

 Melanians. M. De Blainville places it in his family Entomostomata, 

 between Cerithiuni and Planaxli ; and M. Rang, who includes iu it the 

 genus Pirena, between Scalaria and Planaxin. 



The genus Melanopsis was established by M. De Fdrussac, and much 

 difference of opinion appears to have existed among zoologists as to 

 its proper place in the series. M. Deshayes, in the last edition of 

 Lamarck, gives it as his opinion that it should be arranged iu the family 

 of Melaniaus ; and he observes that if one considers the zoological aud 

 conchological characters of the two genera Melania and Melanopsia, 

 the conviction that they should be united soon arises. He remarks 

 that M. De Fdrussac gave, in the first volume of the ' Memoirs of the 

 Society of Natural History of Paris,' an interesting account of the 

 animal of the Melanopsides, which he had observed iu Spaiu in the 

 neighbourhood of Seville and of Valencia, and that M. Quoy has siuco 

 made known the animal of Pirena tercbralis of Lamarck ; so that tho 

 means are now at hand for comparing with exactness the three prin- 

 cipal types of the family of Melaniaus, and of observing the analogy 

 of their zoological characters. 



" If," continues M. Deshayes, " we have before us a great number 

 of species of Melanice and Melanopsides, living aud fossil, we remark 

 a phenomenon entirely similar to that which we have pointed out 

 with relation to the genera Bulimia and Achatina ; that is to say, 

 that we have seen the columellar truncation established by nearly 

 insensible degrees from the most uncertain commencement to a notcli 

 as deep as that which marks theBuccina. If, in relying on the identity 

 of the organisation of the liulimi and A chatinte, we have been able to 

 reduce almost to nothing the value of the character of the eolumellar 

 truncation, we are authorised to employ here the same means for 

 demonstrating the little importance which the truncation of t'ae 

 columella in the Melanopsides ought to have in the eyes of zoologists 

 as a ground for separating them from the Melania. Already we have 

 explained ourselves as to the value of the genus Pirena, aud have 

 shown that it was composed by Lamarck from heterogeneous materials : 

 on one side we find true Melanue, and on the other singular shells, 

 approximating in their characters to certain Ccrithia which Linnaeus 

 compriped among his Strombi. On approximating these species we 

 soon find that they have all the principal characters of Melanopsis, and 

 that they do not in reality differ from them, except by a notch in the 

 right lip, which notch occupies in these species the place of the 

 posterior gutter in the bucciniform Melanopsides. M. De Fdrussac 

 clearly perceived the relation of these shells to the Melanopsides, and 

 joined them to that group, leaving in the genus Pirena only those 

 which we actually comprise atnoug the Melanite. Thus dismembered, 

 the genus Pirena should be expunged from the system." 



M. Deshayes observes that the Melanopsides inhabit the fresh-waters 

 of the south of Europe, and particularly those in the neighbourhood 

 of the Mediterranean; and that they show themselves abundantly iu 

 a fossil state in the greater part of the tertiary beds of Europe. He 

 remarks that M. De Fe'russac has noticed that among the fossil species 

 in our temperate countries there are some analogous to those which 

 live in much warmer regions an interesting fact, from which he has 

 been led to conclude that the lowering of the temperature had been 

 a sufficient cause for the destruction of the races which once lived in 

 the centre of France. M. Deshayes states that he had objected to 

 M. De FcVussac drawing a conclusion so general from so confined a 

 number of observations ; and he thinks that, in order to establish a 

 fact so important as that of change of temperature by the aid of 

 observations on the molluscs, it would be necessary to find a great 

 collection of facts, not only regarding the fresh-water molluscs, but 



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