( 27 ) 



DIVISION XIV. ELL1PSQSTOM AT A . 



GENERA. 



A. Longitudinally volute; the last whorl considerably larger than 

 the -preceding. 



1. Lymn^us. (1) Lam. 



Spire oblong ; thin ; no Columella* with a Ion- In stagnant waters 

 operculum. PI. 6, fig. 12. gitudinal fold entering and marshes. 



obliquely into the mouth. V. Animal, p. 



2. Physa. Drap. . , 

 Spire short or moderate ; Columella simple. 



very thin ; no operculum. 



PI. 6, fig. 13. 



3. Melania. (2) 

 Outer lip advancing and 



narrowing the mouth ; an 

 operculum. 



a. Melania, Lam. 

 Peristoma complete, Turreted. 



effusive (3) at the base 

 of the columella; black. 

 PI. 6, fig. 14. 



b. Melantho. 

 Peristoma incom- Sub-globular. 



plete, not effusive ; very 

 thick : white. PI. 6, 



63. 



In springs. 



V. Animal, p. 63. 



Marine and Fresh 

 Water, 

 V. Animal, p. 67. 



Fluviatic. Isle of France. 

 Madagascar, East Indies. 



Marine. 



fig. 15. 



c. Melanopsis, Lam. 



Peristoma incom- 

 plete, inner lip very 

 broad, reflected, effu- 

 sive ; black. PI. 6, fig. 

 18. 



Turreted. 



Fluviatic. 



Turreted ; spire curved. Marine. 



d. Melanella, Dufresne. 



Semi - transparent, 

 mouth invaded by the 

 last whorl; white. PI. 

 6, fig. 17. 



(1) Foss. in the Cowes Rock of Limestone; Grignon ; 1st and 2nd Fresh Water 

 Formations of the environs of Paris. * See the section PI. 42, fig. 16. 



(2) I have ventured to separate the marine Melaniae, under the name of Melantho, 

 the Melanella (in the cabinet of M. Dufresne), and the Melanamona ; adding the 

 name of Melanatria to Lamarck's Pyrene, in order to indicate its connexion with the 

 others. Foss. in the London Clay; P ur beck Limestone ; Coral Rag; Blue Lias; at 

 Grignon, Courtagnon, Houdan, Parnes and Ponchartrain. The fossil species of Me- 

 lania found at Grignon differ remarkably from the freshwater species. In the M. 

 cosicllata, pi. 13, fig. 44, the peristoma is continuous, but the mouth is not circu- 

 lar, and it is entirely detached from the columella towards the upper part of the 

 lip. In the M. cochlearclla, pi. 13, fig. 13, the lip is prolonged like a spoon ; in the 

 M. marginata y pi. 13, fig. 10, the peristoma is margined or thickened. The fluviatic 

 Melania brought by Olivier from the East are very distinct in appearance from all other 

 species : see PI. 8, fig. 14, 17. This Genus is, probably, entirely foreign to Europe. 



(3) V crsanle is the French term, which they explain by saying if the shell were 

 laid on its back and filled with water, it would run out at this part of the mouth : 

 this has been concluded to be the meaning of Linnaeus's term Effusus, but it appears 

 improbable that he should take a perfect instead of a present participle, when we 

 consider his Latinitv. 



