88 Mr Gray on Testaceous MoUusca. 



sea. This may, however, like some of the smaller Pahidince of 

 Draparnauld, be truly a LHtorina, having a horny and spiral, 

 and not an annular, operculum. 



According to the observations of my sister, Mrs Ince, of Mr 

 Benson, of MM. Quoy and Gaimard, and of M. Lesson, the 

 Indian species of Neritlna like the European, are found only 

 in fresh water ; yet M. Rang, in his Manuel des Mollusques, 

 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 Madagas- 

 car ; General Hardwicke marks on his drawing of the Neritina 

 crepidularis, that it was found in " saltwater lakes, April 1816 ;*" 

 and Say has described the Neritina Meleagris of Lamarck 

 {Theodoxus reclinattts. 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 tropical species often quit 

 the stream and crawl up the trunks of neighbouring trees, on 

 which, like the species of Littorina, Planaocis, and Bidla, 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 Jvicnlcs 

 and Aplysioe ; and I have little doubt that Neritina Pupa in- 

 habits the sea, it being uniformly brought to this country in 

 company with marine shells. 



Many species of Melania, as, for example, M. amarula, M. 

 jfasciolata, and M. lineata, are found in the fresh water streams 

 of India and its islands. Mr Say mentions species found in si- 

 milar situations in North America ; he also describes one (J/. 

 simplex) as found in a stream running through the salt water 

 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; ]\f. 

 Cailliaud 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 Nei'itina just adverted 



• See Zoological Journal, voL v. p. 33. 



