MEL AN I A. 



Plate I. 



Genus MELANIA, Lamarck. 



Testa plus minusve turrita, plerumque plicata vel carinata, 

 olivacea, sape fusco-virente fasciala, spird nunc brevi, 

 nunc elongatd, versus apicem plerumque erosd; colu- 

 mella lavi, arcuatd ; aperturd ovald, inter dum in- 

 tegrd, interdum ad basin sinuato-effusd. 



Shell more or less turreted, generally plicated or keeled, 

 olive, often banded with fuscous green, spire some- 

 times short, sometimes elongated, generally eroded 

 towards the apex, columella smooth, arched; aper- 

 ture ovate, sometimes entire, sometimes sinuously ef- 

 fused at the base. 



The shells of the great family of Melaniadce, inhabiting 

 rapids and tidal rivers within an area of about forty de- 

 grees on either side of the Equator, in both hemispheres, 

 have been little collected and little studied in England. 

 Excepting four small species thinly distributed in the 

 rivers of Dalmatia, Spain, and Portugal, they are unknown 

 in Europe, and I have had to work out the monograph 

 with comparatively limited series of specimens, and, in 

 some instances, with rather doubtful or misnamed types. 

 Mr. Cuming's specimens, greatly enriched by those col- 

 lected by him in the Philippine Islands, had, however, 

 been sent for examination and description to Mr. Lea, of 

 Philadelphia; and Mr. Anthony, of Cincinnati, most kindly 

 forwarded to me his types of the principal species of the 

 Southern United States. The types of the species col- 

 lected by Mr. Hinds, in the Peejee and adjacent islands, 

 together with several collected in India, Guiana, and Per- 

 nambuco, have been placed at my service ; and I have to 

 thank M. Morelet, of Dijon, for the loan of the very in- 

 teresting specimens collected by him in Central America, 

 as well as Dr. von dem Buseh, of Bremen, for the loan of 

 an extensive series, including several species described by 

 Continental authors, which would not have been other- 

 wise known to me. 



After laying aside the Melaniad<r already published in 

 the monographs of the genera To, Hemisinus, Anculotus, 

 Melatoma, Pirena, Melanopsis, and Paludomus, about 470 

 species remain to the genus Melania. More have been 

 described, but these are all of which I have succeeded in 

 procuring the shell. Advantage might have been taken 

 of the labours of systematists to have distributed them into 

 further genera — Tiara, Pachychilus, CeripAasia, Clea, Me- 

 lanella — but more materials are needed for their elucida- 



tion than we at present possess. The largest species of 

 Melania are those collected by Mr. Cuming in the rivers 

 of the Philippine Islands, chiefly the island of Luzon, and 

 by M. Morelet, in Central America ; the most abundant, 

 both in individuals and in species, but of uniformly smaller 

 size, are those of the great rivers of the Southern United 

 States. A few of large size, including the very charac- 

 teristic M. tuberculosa, are natives of West Africa ; and the 

 rivers Branca, Essequibo, and Maranon, in Guiana and 

 North Brazil, contribute a few fine species. 



Out of the 470 species described in the present mono- 

 graph, we have authority for the habitats of 410, as fol- 

 lows :• — 



Eastern Hemisphere. 



Southern Europe 4 



Egypt and Abyssinia 3 



West Africa and Cape de Verd Islands . 24 



South Africa 1 



Mauritius and Madagascar 4 



Japan 1 



China 4 



Ceylon 5 



Java, and adjacent islands 25 



Philippine Islands 38 



Borneo and Celebes 10 



Feejee and adjacent islands, including New 



Caledonia 20 



Sandwich and adjacent islands .... 5 

 North Australia 1 



New Zealand 1 



155 



Western Hemisphere. 



North Brazil, Guiana, Pernambuco . . 10 



Oregon, California, Cuba 10 



Central America 25 



Southern United States 21 



255 



410 



The animal of the Melaniadce is a pectinate-gilled mol- 

 lusk, breathing only in water, with a short slight disk and 

 a truncated subcorneal proboscis-shaped head, with the 

 tentacles distant and subulate, having the eyes on the 

 outer side sometimes at the base, sometimes more ad- 

 vanced ; the mantle is fringed ; operculum horny. 



June, 1861. 



