GASTEROPODA PULMONEA. 337 



nearly in one plane, and because the aperture is wider than it is 

 high. It contains an animal with long, thin, filiform tentacula, at 

 the inner base of which are the eyes, and from the margin of whose 

 mantle exudes a quantity of a red fluid, which is not, however, its 

 blood. Its stomach is muscular and its food vegetable, like that of 

 the Limnaei, of which, in all our stagnant waters, it is the faithful 

 companion. The 



LiMN^us, Lam.(l) 



Separated from the Bulimi of Brugiere by M. Delamark, has, like 

 a Bulimus, an oblong spine and the aperture higher than it is wide- 

 but the margin, like that of a Succinea, is not reflected, and there 

 is a longitudinal fold in the columella, which runs obliquely into the 

 cavity. The shell is thin; the animal has two compressed, broad, 

 triangular tentacula, near the base of whose inner edge are the eyes. 

 They feed on plants and seeds, and their stomach is a very muscular 

 gizzard, preceded by a crop. Like all the Pulmonea, they are her- 

 maphrodites, and the female organ of generation being far from the 

 other, they are compelled so to copulate, that the individual which 

 acts as a male for one, serves as a female for a thirdj long strings of 

 them may be observed in this position. 



They inhabit stagnant waters in great numbers; they also abound 

 with the Planorbes in certain layers of marl or calcareous strata, 

 which they evidently prove were deposited in fresh water(2). 



Physa, Drap. 



The Physae, which were gratuitously placed among the Bullae, 

 have a shell very similar to that of a Lymnaea, but without the fold 

 in the columella and reflected edge, and very thin. When the ani- 

 mal swims or crawls, it covers its shell with the two notched lobes 

 of its mantle, and has two long, slender and pointed tentacula, on 

 the greatly enlarged internal base of which are the eyes. They in- 

 habit springs, &c. 



One of them, Bulla fontinalis, L., which is sinistral, is found 

 in France(3). 



See the quotations of Gmel., and add, Draparnaud, pi. I, f. r>9 — 51, and pi. ii, 

 f. 1—22. 



(1) Hel. stagnalis, L., of which H. fragilis is a variety; — H. palustris; — H. pe- 

 regra; — H. limosa,- — H. auricularia. See Drap., pi. ii, f. 28, 42, and pi. iii, f. 1,7. 



(2) The mantle of the Limn, glutinoms, like that of the Physse, is sufficiently 

 ample to envelope its shell. Itisthe genus Amphipeplf.a, Nilson, Moll. succ. 



(3) The neighbouring species, Bull, hypnorum, L., &nd Physa acuta, and Scat- 

 uriginum, Drap., require an examination of their animals. Fide, Drap., p. 54. 

 et seq. 



Vol. II.— 2 S 



