MR. GRAY ON TESTACEOUS MOLLUSCA. 307 



fotind on the shores of the sea near Trelleborg. All the species of Paludina and Bithy- 

 nia which have fallen under my own observation are essentially fluviatile ; but M. 

 NiLssoN refers in the paragraph above quoted to a species of the former genus inhabit- 

 ing the sea. This may, however, like some of the smaller Paludinoe of Draparnauld, 

 be truly a Littorina, having a horny and spiral, and not an annular, operculum. 



According to the observations of my sister, Mrs. Ince, of Mr. Benson, of MM. 

 Quovand Gaimard, and of M. Lesson, the Indian species of Neritina, like the Euro- 

 pean, are found only in fresh water ; yet M, Rang, in his Manuel des MoUusques, 

 p. 193, states that the Neritina viridis is a marine species found on rocks covered by 

 the sea at Martinique, and that a larger variety of this species is found in similar 

 situations at Madagascar ; General Hardwicke marks on his drawing of the Neritina 

 crepidularis, that it was found in "saltwater lakes, April 1816;" and Say has de- 

 scribed the Neritina Meleagris of Lamarck {Theodoxus reclinatus, Say,) as living both 

 in fresh and salt water. This is most probably the species to which Mr. Guilding 

 refers*, when he observes that he has kept Neritina for some time alive in a close 

 vessel of salt water, which they appear to purify. The animals of some of the tro- 

 pical species often quit the stream and crawl up the trunks of neighbouring trees, on 

 which, like the species of Littorina^ Planaxis, and Bulla, which creep up the rocks on 

 the sea-coast, they attach themselves, and remain exposed to the influence of the 

 sun. It may be added, that M. Rang has found Neritina Auricula in brackish 

 marshes near the sea in the Island of Bourbon, in company with Aviculce and Aply- 

 sice ; and I have little doubt that Neritina Pupa inhabits the sea, it being uniformly 

 brought to this country in company with marine shells. 



Many species of Melania, as, for example, M. amarula, M. fasciolata, and M. lineata, 

 are found in the freshwater streams of India and its islands. Mr. Say mentions 

 species found in similar situations in North America ; he also describes one {M. sim- 

 plex) as found in a stream running through the saltwater valley near the salt-works, 

 but does not state whether the water of the stream is salt or fresh. On the other 

 hand, M. Quoy asserts that they are sometimes taken in brackish water ; M. Cail- 

 LiAUD states that Melania Oweni is found in brackish water ; and M. Rang has 

 found other species in the Island of Bourbon under the same circumstances with the 

 Neritina just adverted to. The genus Melanopsis has the same habits ; its species 

 are often found in large inland lakes. I have myself received M. huccinoidea from 

 the sea of Galilee ; and Dr. Clark, in his Travels, vol. ii. p. 243, figures M. Dufourii 

 under the name of Buccinum Galileum. The water of this lake, however, unlike that 

 of the neighbouring Dead Sea, is, according to the statement of Fuller, perfectly 

 fresh and sweet. M. Lesson, on the other hand, states that he found the Pyrena 

 terebrans, regarded by M. de Ferussac as a Melanopsis, in great abundance in 

 brackish marshes in New Guinea, and at the Island of Bourou. 



I am informed by Mr. Sowerby that some species of the fluviatile genus Cyrena 

 are found in the sea on the coast of South America ; but he thinks it probable that 



* See Zoological Journal, vol. /. n. 32 



