“> 
& 
1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 105 
CASSIDULA Férussac 
Auricula subgenus Cassidula Férussac, 1821 (2), ‘Tabl. Systém. An. Moll., 
Tabl. Systém. Limagons,’ p. 105. Type by designation of Gray (1847, Proce. Zodl. 
Soc. London, p. 179): Auricula felis Lamarck = Bulimus auris-felis Bruguiére. 
Sidula Gray, 1840, in Turton’s ‘Manual Shells Brit. Isl.,’ 2d Ed., p. 21. Mono- 
type: Sidula felis Catti=Bulimus auris-felis Bruguiére. : 
One species is found on the coast of South Africa: 
Cassidula labrella (Deshayes) = Auricula labrella DrsHAyYEs, 1830, ‘Encyclop. 
Méthod., Vers,’ {1, p. 92. Cassidula lutescens Preirrer, 1856, ‘Monogr. Auriculac.,’ 
p. 113. Auricula kraussi Kiisrer, 1841, in Martini and Chemnitz, ‘Syst. Conch. 
Cab., I, 16, Auriculacea,’ 1, p. 24, Pl. m1, figs. 6-8. Described from Mauritius; has 
been found on the coast of Natal. 
Lymneide! 
Shell elongate, generally dextral, thin, with prominent or short, tapering spire 
and ovate or rotund aperture; the columellar axis is covered with a shelly deposit 
and generally gyrate or twisted; peristome thin, sometimes expanded or with a thin 
internal varix. The thin periostracum is usually pale and uniform, rarely banded, 
and sometimes showing dark underlying streaks. 
The broad head bears triangular, flattened tentacles with the eyes at their inner 
bases. Foot rather short, rounded posteriorly. Radula with narrow, unicuspid cen- 
tral teeth, bicuspid or tricuspid laterals, serrate marginals. Jaw with accessory 
lateral pieces. Kidney wide and pear-shaped, with direct ureter. Male organ is 
divided into a slender and a wide section, both provided with retractor muscles. 
Oviparous. Air-breathing, not provided with a pseudobranch. 
This family is of world-wide distribution in fresh water. 
Lymnza Lamarck ~ 
Lymnxa Lamarck, 1799, Mém. Soc. Hist. Nat. Paris, p. 75. Monotype: Helix 
> stagnalis Linneus. 
Lymnus Denys DE Montrort, 1810, ‘Conchyl. Systém.,’ IT, p. 262. Monotype: 
Lymnexa stagnalis Linnzus. 
Lymnula RAFINESQUE, 1819, Journ. de Physique, LX XXVIII, p. 428. Sub- 
stitute for Lymnxa. Type: Helix stagnalis Linnzeus, as fixed by Pilsbry, 1917, The 
Nautilus, XXX, p. 113. | 
Inmneus DRAPARNAUD, 1805, ‘Hist. Nat. Moll. Terr. Fluv. France,’ pp. 25, 
28, and 48. Different spelling of Lymnza. 
Lymnaeus Cuvier, 1817, ‘Régne Animal,’ II, p. 412. Different spelling of 
Lymnea. 7 
Leachia “Risso” JEFFREYS, 1833, Trans. Linn. Soc. London, XVI, 3, p. 519. 
Type: Limneus major Jeffreys= Helix stagnalis Linnzeus. 
Limnea FLEMING, 1828, ‘Hist. British Anim.,’ p. 273. Different spelling of 
Lymnexa. 
1In drawing up the characters of this family and its subdivisions we have made use of the results 
of F.C. Baker’s investigations as contained in his excellent monograph, ‘ Lymneide of North and Middle 
America’ (1911, Chicago Ac. Sci., Special Publ. No. 3, xvi+539 pp., 58 Pls.). 
