190 BRITISH MOLLUSKS. 



the umbilicus is small, and almost closed by the compression of the 

 reflected columellar lip. It chiefly inhabits muddy places in slowly 

 running and still waters. 



3. Bythinia Leachii. Leach's BytMnia. 



Shell ; conically turbinated, somewhat scalariform, minutely umbi 



Heated, pale semitransparent fulvous 



green, whorls five, rather narrow, 



rounded, smooth ; aperture rather 



small, rounded, but little pyriform. 



Opercidum spirally striated around a 



central nucleus. 

 Paludina ventricosa, Gray (1821), Lond. Med. 



Pepos. vol. xv. p. 239 (without characters 



or figure). 

 Turbo Leachii, Sheppard (1823), Trans. Linn. Soc. vol. xiv. p. 152. 

 Paludina acuta, Fleming (1828), Brit. Anim. p. 315. 

 Paludina Kickxii, Yestencl (1835), Bull. Acad. Brux. vol. iii. p. 375. 

 Bithinia ventricosa, Gray (1840), Turt. Man. p. 94. pi. x. f. 121. 

 Paludina decipiens, Millet (1843), Mag. de Zool. p. 2. pi. lxiv. f. 2. 

 Paludina ventricosa, Brown (1845), Illus. Conch. Brit. p. 27. pi. xiv. f. 74, 



75. 

 Paludina Michaudi, Duval (1845), Pev. Zool. Soc. Cuv. p. 211. 

 Bithinia Kickxii and Michaudi, Dupuy (1849), Cat. LJxtram. Test. no. 41 



and 43. 

 BytMnia (JSlona) Leachii, Moquin-Tandon (1855), Hist. Moll. vol. ii. 



p. 527. pi. xxxix. f. 20 to 22. 

 Sab. Throughout Europe. North Africa. (In gentle streams and still 



waters.) 

 This species is distinguished from the preceding, in being very 

 much smaller and less ventricose. The whorls of the shell are 

 rather narrow, rounder, and more loosely convoluted than in B. ten- 

 taculata, and they have a scalariform appearance. It is equally 

 widely diffused, but is rather scarcer and more local. Southwards 

 it passes into Algeria. The animal is speckled with black and 

 yellow upon a light grey ground. 



Dr. Gray mentions that the eggs of this species are disposed, in a 

 double row of six or seven pairs, on a tough strap-shaped green 

 membrane attached to aquatic plants. 



